mirror of
https://github.com/c64scene-ar/llvm-6502.git
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b1ccfb3a54
If "C1/X" were having multiple uses, the only benefit of this transformation is to potentially shorten critical path. But it is at the cost of instroducing additional div. The additional div may or may not incur cost depending on how div is implemented. If it is implemented using Newton–Raphson iteration, it dosen't seem to incur any cost (FIXME). However, if the div blocks the entire pipeline, that sounds to be pretty expensive. Let CodeGen to take care this transformation. This patch sees 6% on a benchmark. rdar://15032743 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191037 91177308-0d34-0410-b5e6-96231b3b80d8
480 lines
13 KiB
LLVM
480 lines
13 KiB
LLVM
; RUN: opt < %s -instcombine -S | FileCheck %s
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; testing-case "float fold(float a) { return 1.2f * a * 2.3f; }"
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; 1.2f and 2.3f is supposed to be fold.
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define float @fold(float %a) {
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%mul = fmul fast float %a, 0x3FF3333340000000
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%mul1 = fmul fast float %mul, 0x4002666660000000
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ret float %mul1
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; CHECK-LABEL: @fold(
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; CHECK: fmul fast float %a, 0x4006147AE0000000
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}
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; Same testing-case as the one used in fold() except that the operators have
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; fixed FP mode.
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define float @notfold(float %a) {
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; CHECK-LABEL: @notfold(
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; CHECK: %mul = fmul fast float %a, 0x3FF3333340000000
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%mul = fmul fast float %a, 0x3FF3333340000000
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%mul1 = fmul float %mul, 0x4002666660000000
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ret float %mul1
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}
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define float @fold2(float %a) {
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; CHECK-LABEL: @fold2(
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; CHECK: fmul fast float %a, 0x4006147AE0000000
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%mul = fmul float %a, 0x3FF3333340000000
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%mul1 = fmul fast float %mul, 0x4002666660000000
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ret float %mul1
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}
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; C * f1 + f1 = (C+1) * f1
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define double @fold3(double %f1) {
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%t1 = fmul fast double 2.000000e+00, %f1
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%t2 = fadd fast double %f1, %t1
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ret double %t2
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; CHECK-LABEL: @fold3(
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; CHECK: fmul fast double %f1, 3.000000e+00
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}
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; (C1 - X) + (C2 - Y) => (C1+C2) - (X + Y)
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define float @fold4(float %f1, float %f2) {
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%sub = fsub float 4.000000e+00, %f1
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%sub1 = fsub float 5.000000e+00, %f2
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%add = fadd fast float %sub, %sub1
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ret float %add
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; CHECK-LABEL: @fold4(
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; CHECK: %1 = fadd fast float %f1, %f2
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; CHECK: fsub fast float 9.000000e+00, %1
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}
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; (X + C1) + C2 => X + (C1 + C2)
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define float @fold5(float %f1, float %f2) {
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%add = fadd float %f1, 4.000000e+00
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%add1 = fadd fast float %add, 5.000000e+00
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ret float %add1
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; CHECK-LABEL: @fold5(
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; CHECK: fadd fast float %f1, 9.000000e+00
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}
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; (X + X) + X => 3.0 * X
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define float @fold6(float %f1) {
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%t1 = fadd fast float %f1, %f1
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%t2 = fadd fast float %f1, %t1
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ret float %t2
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; CHECK-LABEL: @fold6(
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; CHECK: fmul fast float %f1, 3.000000e+00
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}
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; C1 * X + (X + X) = (C1 + 2) * X
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define float @fold7(float %f1) {
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%t1 = fmul fast float %f1, 5.000000e+00
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%t2 = fadd fast float %f1, %f1
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%t3 = fadd fast float %t1, %t2
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ret float %t3
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; CHECK-LABEL: @fold7(
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; CHECK: fmul fast float %f1, 7.000000e+00
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}
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; (X + X) + (X + X) => 4.0 * X
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define float @fold8(float %f1) {
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%t1 = fadd fast float %f1, %f1
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%t2 = fadd fast float %f1, %f1
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%t3 = fadd fast float %t1, %t2
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ret float %t3
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; CHECK: fold8
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; CHECK: fmul fast float %f1, 4.000000e+00
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}
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; X - (X + Y) => 0 - Y
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define float @fold9(float %f1, float %f2) {
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%t1 = fadd float %f1, %f2
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%t3 = fsub fast float %f1, %t1
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ret float %t3
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; CHECK-LABEL: @fold9(
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; CHECK: fsub fast float 0.000000e+00, %f2
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}
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; Let C3 = C1 + C2. (f1 + C1) + (f2 + C2) => (f1 + f2) + C3 instead of
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; "(f1 + C3) + f2" or "(f2 + C3) + f1". Placing constant-addend at the
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; top of resulting simplified expression tree may potentially reveal some
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; optimization opportunities in the super-expression trees.
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;
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define float @fold10(float %f1, float %f2) {
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%t1 = fadd fast float 2.000000e+00, %f1
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%t2 = fsub fast float %f2, 3.000000e+00
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%t3 = fadd fast float %t1, %t2
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ret float %t3
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; CHECK-LABEL: @fold10(
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; CHECK: %t3 = fadd fast float %t2, -1.000000e+00
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; CHECK: ret float %t3
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}
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; once cause Crash/miscompilation
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define float @fail1(float %f1, float %f2) {
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%conv3 = fadd fast float %f1, -1.000000e+00
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%add = fadd fast float %conv3, %conv3
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%add2 = fadd fast float %add, %conv3
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ret float %add2
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; CHECK-LABEL: @fail1(
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; CHECK: ret
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}
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define double @fail2(double %f1, double %f2) {
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%t1 = fsub fast double %f1, %f2
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%t2 = fadd fast double %f1, %f2
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%t3 = fsub fast double %t1, %t2
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ret double %t3
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; CHECK-LABEL: @fail2(
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; CHECK: ret
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}
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; c1 * x - x => (c1 - 1.0) * x
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define float @fold13(float %x) {
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%mul = fmul fast float %x, 7.000000e+00
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%sub = fsub fast float %mul, %x
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ret float %sub
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; CHECK: fold13
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; CHECK: fmul fast float %x, 6.000000e+00
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; CHECK: ret
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}
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; =========================================================================
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;
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; Testing-cases about fmul begin
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;
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; =========================================================================
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; ((X*C1) + C2) * C3 => (X * (C1*C3)) + (C2*C3) (i.e. distribution)
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define float @fmul_distribute1(float %f1) {
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%t1 = fmul float %f1, 6.0e+3
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%t2 = fadd float %t1, 2.0e+3
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%t3 = fmul fast float %t2, 5.0e+3
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ret float %t3
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; CHECK-LABEL: @fmul_distribute1(
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; CHECK: %1 = fmul fast float %f1, 3.000000e+07
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; CHECK: %t3 = fadd fast float %1, 1.000000e+07
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}
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; (X/C1 + C2) * C3 => X/(C1/C3) + C2*C3
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define double @fmul_distribute2(double %f1, double %f2) {
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%t1 = fdiv double %f1, 3.0e+0
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%t2 = fadd double %t1, 5.0e+1
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; 0x10000000000000 = DBL_MIN
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%t3 = fmul fast double %t2, 0x10000000000000
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ret double %t3
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; CHECK-LABEL: @fmul_distribute2(
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; CHECK: %1 = fdiv fast double %f1, 0x7FE8000000000000
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; CHECK: fadd fast double %1, 0x69000000000000
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}
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; 5.0e-1 * DBL_MIN yields denormal, so "(f1*3.0 + 5.0e-1) * DBL_MIN" cannot
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; be simplified into f1 * (3.0*DBL_MIN) + (5.0e-1*DBL_MIN)
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define double @fmul_distribute3(double %f1) {
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%t1 = fdiv double %f1, 3.0e+0
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%t2 = fadd double %t1, 5.0e-1
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%t3 = fmul fast double %t2, 0x10000000000000
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ret double %t3
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; CHECK-LABEL: @fmul_distribute3(
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; CHECK: fmul fast double %t2, 0x10000000000000
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}
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; ((X*C1) + C2) * C3 => (X * (C1*C3)) + (C2*C3) (i.e. distribution)
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define float @fmul_distribute4(float %f1) {
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%t1 = fmul float %f1, 6.0e+3
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%t2 = fsub float 2.0e+3, %t1
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%t3 = fmul fast float %t2, 5.0e+3
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ret float %t3
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; CHECK-LABEL: @fmul_distribute4(
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; CHECK: %1 = fmul fast float %f1, 3.000000e+07
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; CHECK: %t3 = fsub fast float 1.000000e+07, %1
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}
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; C1/X * C2 => (C1*C2) / X
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define float @fmul2(float %f1) {
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%t1 = fdiv float 2.0e+3, %f1
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%t3 = fmul fast float %t1, 6.0e+3
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ret float %t3
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; CHECK-LABEL: @fmul2(
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; CHECK: fdiv fast float 1.200000e+07, %f1
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}
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; X/C1 * C2 => X * (C2/C1) is disabled if X/C1 has multiple uses
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@fmul2_external = external global float
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define float @fmul2_disable(float %f1) {
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%div = fdiv fast float 1.000000e+00, %f1
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store float %div, float* @fmul2_external
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%mul = fmul fast float %div, 2.000000e+00
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ret float %mul
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; CHECK-LABEL: @fmul2_disable
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; CHECK: store
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; CHECK: fmul fast
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}
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; X/C1 * C2 => X * (C2/C1) (if C2/C1 is normal Fp)
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define float @fmul3(float %f1, float %f2) {
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%t1 = fdiv float %f1, 2.0e+3
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%t3 = fmul fast float %t1, 6.0e+3
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ret float %t3
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; CHECK-LABEL: @fmul3(
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; CHECK: fmul fast float %f1, 3.000000e+00
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}
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; Rule "X/C1 * C2 => X * (C2/C1) is not applicable if C2/C1 is either a special
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; value of a denormal. The 0x3810000000000000 here take value FLT_MIN
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;
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define float @fmul4(float %f1, float %f2) {
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%t1 = fdiv float %f1, 2.0e+3
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%t3 = fmul fast float %t1, 0x3810000000000000
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ret float %t3
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; CHECK-LABEL: @fmul4(
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; CHECK: fmul fast float %t1, 0x3810000000000000
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}
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; X / C1 * C2 => X / (C2/C1) if C1/C2 is either a special value of a denormal,
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; and C2/C1 is a normal value.
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;
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define float @fmul5(float %f1, float %f2) {
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%t1 = fdiv float %f1, 3.0e+0
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%t3 = fmul fast float %t1, 0x3810000000000000
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ret float %t3
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; CHECK-LABEL: @fmul5(
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; CHECK: fdiv fast float %f1, 0x47E8000000000000
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}
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; (X*Y) * X => (X*X) * Y
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define float @fmul6(float %f1, float %f2) {
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%mul = fmul float %f1, %f2
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%mul1 = fmul fast float %mul, %f1
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ret float %mul1
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; CHECK-LABEL: @fmul6(
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; CHECK: fmul fast float %f1, %f1
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}
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; "(X*Y) * X => (X*X) * Y" is disabled if "X*Y" has multiple uses
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define float @fmul7(float %f1, float %f2) {
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%mul = fmul float %f1, %f2
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%mul1 = fmul fast float %mul, %f1
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%add = fadd float %mul1, %mul
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ret float %add
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; CHECK-LABEL: @fmul7(
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; CHECK: fmul fast float %mul, %f1
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}
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; =========================================================================
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;
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; Testing-cases about negation
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;
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; =========================================================================
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define float @fneg1(float %f1, float %f2) {
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%sub = fsub float -0.000000e+00, %f1
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%sub1 = fsub nsz float 0.000000e+00, %f2
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%mul = fmul float %sub, %sub1
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ret float %mul
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; CHECK-LABEL: @fneg1(
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; CHECK: fmul float %f1, %f2
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}
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; =========================================================================
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;
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; Testing-cases about div
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;
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; =========================================================================
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; X/C1 / C2 => X * (1/(C2*C1))
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define float @fdiv1(float %x) {
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%div = fdiv float %x, 0x3FF3333340000000
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%div1 = fdiv fast float %div, 0x4002666660000000
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ret float %div1
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; 0x3FF3333340000000 = 1.2f
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; 0x4002666660000000 = 2.3f
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; 0x3FD7303B60000000 = 0.36231884057971014492
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; CHECK-LABEL: @fdiv1(
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; CHECK: fmul fast float %x, 0x3FD7303B60000000
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}
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; X*C1 / C2 => X * (C1/C2)
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define float @fdiv2(float %x) {
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%mul = fmul float %x, 0x3FF3333340000000
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%div1 = fdiv fast float %mul, 0x4002666660000000
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ret float %div1
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; 0x3FF3333340000000 = 1.2f
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; 0x4002666660000000 = 2.3f
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; 0x3FE0B21660000000 = 0.52173918485641479492
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; CHECK-LABEL: @fdiv2(
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; CHECK: fmul fast float %x, 0x3FE0B21660000000
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}
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; "X/C1 / C2 => X * (1/(C2*C1))" is disabled (for now) is C2/C1 is a denormal
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;
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define float @fdiv3(float %x) {
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%div = fdiv float %x, 0x47EFFFFFE0000000
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%div1 = fdiv fast float %div, 0x4002666660000000
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ret float %div1
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; CHECK-LABEL: @fdiv3(
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; CHECK: fdiv float %x, 0x47EFFFFFE0000000
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}
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; "X*C1 / C2 => X * (C1/C2)" is disabled if C1/C2 is a denormal
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define float @fdiv4(float %x) {
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%mul = fmul float %x, 0x47EFFFFFE0000000
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%div = fdiv float %mul, 0x3FC99999A0000000
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ret float %div
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; CHECK-LABEL: @fdiv4(
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; CHECK: fmul float %x, 0x47EFFFFFE0000000
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}
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; (X/Y)/Z = > X/(Y*Z)
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define float @fdiv5(float %f1, float %f2, float %f3) {
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%t1 = fdiv float %f1, %f2
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%t2 = fdiv fast float %t1, %f3
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ret float %t2
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; CHECK-LABEL: @fdiv5(
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; CHECK: fmul float %f2, %f3
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}
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; Z/(X/Y) = > (Z*Y)/X
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define float @fdiv6(float %f1, float %f2, float %f3) {
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%t1 = fdiv float %f1, %f2
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%t2 = fdiv fast float %f3, %t1
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ret float %t2
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; CHECK-LABEL: @fdiv6(
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; CHECK: fmul float %f3, %f2
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}
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; C1/(X*C2) => (C1/C2) / X
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define float @fdiv7(float %x) {
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%t1 = fmul float %x, 3.0e0
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%t2 = fdiv fast float 15.0e0, %t1
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ret float %t2
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; CHECK-LABEL: @fdiv7(
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; CHECK: fdiv fast float 5.000000e+00, %x
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}
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; C1/(X/C2) => (C1*C2) / X
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define float @fdiv8(float %x) {
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%t1 = fdiv float %x, 3.0e0
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%t2 = fdiv fast float 15.0e0, %t1
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ret float %t2
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; CHECK-LABEL: @fdiv8(
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; CHECK: fdiv fast float 4.500000e+01, %x
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}
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; C1/(C2/X) => (C1/C2) * X
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define float @fdiv9(float %x) {
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%t1 = fdiv float 3.0e0, %x
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%t2 = fdiv fast float 15.0e0, %t1
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ret float %t2
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; CHECK-LABEL: @fdiv9(
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; CHECK: fmul fast float %x, 5.000000e+00
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}
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; =========================================================================
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;
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; Testing-cases about factorization
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;
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; =========================================================================
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; x*z + y*z => (x+y) * z
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define float @fact_mul1(float %x, float %y, float %z) {
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%t1 = fmul fast float %x, %z
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%t2 = fmul fast float %y, %z
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%t3 = fadd fast float %t1, %t2
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ret float %t3
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; CHECK-LABEL: @fact_mul1(
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; CHECK: fmul fast float %1, %z
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}
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; z*x + y*z => (x+y) * z
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define float @fact_mul2(float %x, float %y, float %z) {
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%t1 = fmul fast float %z, %x
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%t2 = fmul fast float %y, %z
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%t3 = fsub fast float %t1, %t2
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ret float %t3
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; CHECK-LABEL: @fact_mul2(
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; CHECK: fmul fast float %1, %z
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}
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; z*x - z*y => (x-y) * z
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define float @fact_mul3(float %x, float %y, float %z) {
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%t2 = fmul fast float %z, %y
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%t1 = fmul fast float %z, %x
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%t3 = fsub fast float %t1, %t2
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ret float %t3
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; CHECK-LABEL: @fact_mul3(
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; CHECK: fmul fast float %1, %z
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}
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; x*z - z*y => (x-y) * z
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define float @fact_mul4(float %x, float %y, float %z) {
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%t1 = fmul fast float %x, %z
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%t2 = fmul fast float %z, %y
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%t3 = fsub fast float %t1, %t2
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ret float %t3
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; CHECK-LABEL: @fact_mul4(
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; CHECK: fmul fast float %1, %z
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}
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; x/y + x/z, no xform
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define float @fact_div1(float %x, float %y, float %z) {
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%t1 = fdiv fast float %x, %y
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|
%t2 = fdiv fast float %x, %z
|
|
%t3 = fadd fast float %t1, %t2
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|
ret float %t3
|
|
; CHECK: fact_div1
|
|
; CHECK: fadd fast float %t1, %t2
|
|
}
|
|
|
|
; x/y + z/x; no xform
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|
define float @fact_div2(float %x, float %y, float %z) {
|
|
%t1 = fdiv fast float %x, %y
|
|
%t2 = fdiv fast float %z, %x
|
|
%t3 = fadd fast float %t1, %t2
|
|
ret float %t3
|
|
; CHECK: fact_div2
|
|
; CHECK: fadd fast float %t1, %t2
|
|
}
|
|
|
|
; y/x + z/x => (y+z)/x
|
|
define float @fact_div3(float %x, float %y, float %z) {
|
|
%t1 = fdiv fast float %y, %x
|
|
%t2 = fdiv fast float %z, %x
|
|
%t3 = fadd fast float %t1, %t2
|
|
ret float %t3
|
|
; CHECK: fact_div3
|
|
; CHECK: fdiv fast float %1, %x
|
|
}
|
|
|
|
; y/x - z/x => (y-z)/x
|
|
define float @fact_div4(float %x, float %y, float %z) {
|
|
%t1 = fdiv fast float %y, %x
|
|
%t2 = fdiv fast float %z, %x
|
|
%t3 = fsub fast float %t1, %t2
|
|
ret float %t3
|
|
; CHECK: fact_div4
|
|
; CHECK: fdiv fast float %1, %x
|
|
}
|
|
|
|
; y/x - z/x => (y-z)/x is disabled if y-z is denormal.
|
|
define float @fact_div5(float %x) {
|
|
%t1 = fdiv fast float 0x3810000000000000, %x
|
|
%t2 = fdiv fast float 0x3800000000000000, %x
|
|
%t3 = fadd fast float %t1, %t2
|
|
ret float %t3
|
|
; CHECK: fact_div5
|
|
; CHECK: fdiv fast float 0x3818000000000000, %x
|
|
}
|
|
|
|
; y/x - z/x => (y-z)/x is disabled if y-z is denormal.
|
|
define float @fact_div6(float %x) {
|
|
%t1 = fdiv fast float 0x3810000000000000, %x
|
|
%t2 = fdiv fast float 0x3800000000000000, %x
|
|
%t3 = fsub fast float %t1, %t2
|
|
ret float %t3
|
|
; CHECK: fact_div6
|
|
; CHECK: %t3 = fsub fast float %t1, %t2
|
|
}
|