Quentin Colombet c5a4c25b87 Fix a bug in instcombine for fmul in fast math mode.
The instcombine recognized pattern looks like:
a = b * c
d = a +/- Cst
or
a = b * c
d = Cst +/- a

When creating the new operands for fadd or fsub instruction following the related fmul, the first operand was created with the second original operand (M0 was created with C1) and the second with the first (M1 with Opnd0).

The fix consists in creating the new operands with the appropriate original operand, i.e., M0 with Opnd0 and M1 with C1.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176300 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-28 21:12:40 +00:00

353 lines
9.5 KiB
LLVM

; RUN: opt < %s -instcombine -S | FileCheck %s
; testing-case "float fold(float a) { return 1.2f * a * 2.3f; }"
; 1.2f and 2.3f is supposed to be fold.
define float @fold(float %a) {
%mul = fmul fast float %a, 0x3FF3333340000000
%mul1 = fmul fast float %mul, 0x4002666660000000
ret float %mul1
; CHECK: @fold
; CHECK: fmul fast float %a, 0x4006147AE0000000
}
; Same testing-case as the one used in fold() except that the operators have
; fixed FP mode.
define float @notfold(float %a) {
; CHECK: @notfold
; CHECK: %mul = fmul fast float %a, 0x3FF3333340000000
%mul = fmul fast float %a, 0x3FF3333340000000
%mul1 = fmul float %mul, 0x4002666660000000
ret float %mul1
}
define float @fold2(float %a) {
; CHECK: @fold2
; CHECK: fmul fast float %a, 0x4006147AE0000000
%mul = fmul float %a, 0x3FF3333340000000
%mul1 = fmul fast float %mul, 0x4002666660000000
ret float %mul1
}
; C * f1 + f1 = (C+1) * f1
define double @fold3(double %f1) {
%t1 = fmul fast double 2.000000e+00, %f1
%t2 = fadd fast double %f1, %t1
ret double %t2
; CHECK: @fold3
; CHECK: fmul fast double %f1, 3.000000e+00
}
; (C1 - X) + (C2 - Y) => (C1+C2) - (X + Y)
define float @fold4(float %f1, float %f2) {
%sub = fsub float 4.000000e+00, %f1
%sub1 = fsub float 5.000000e+00, %f2
%add = fadd fast float %sub, %sub1
ret float %add
; CHECK: @fold4
; CHECK: %1 = fadd fast float %f1, %f2
; CHECK: fsub fast float 9.000000e+00, %1
}
; (X + C1) + C2 => X + (C1 + C2)
define float @fold5(float %f1, float %f2) {
%add = fadd float %f1, 4.000000e+00
%add1 = fadd fast float %add, 5.000000e+00
ret float %add1
; CHECK: @fold5
; CHECK: fadd fast float %f1, 9.000000e+00
}
; (X + X) + X => 3.0 * X
define float @fold6(float %f1) {
%t1 = fadd fast float %f1, %f1
%t2 = fadd fast float %f1, %t1
ret float %t2
; CHECK: @fold6
; CHECK: fmul fast float %f1, 3.000000e+00
}
; C1 * X + (X + X) = (C1 + 2) * X
define float @fold7(float %f1) {
%t1 = fmul fast float %f1, 5.000000e+00
%t2 = fadd fast float %f1, %f1
%t3 = fadd fast float %t1, %t2
ret float %t3
; CHECK: @fold7
; CHECK: fmul fast float %f1, 7.000000e+00
}
; (X + X) + (X + X) => 4.0 * X
define float @fold8(float %f1) {
%t1 = fadd fast float %f1, %f1
%t2 = fadd fast float %f1, %f1
%t3 = fadd fast float %t1, %t2
ret float %t3
; CHECK: fold8
; CHECK: fmul fast float %f1, 4.000000e+00
}
; X - (X + Y) => 0 - Y
define float @fold9(float %f1, float %f2) {
%t1 = fadd float %f1, %f2
%t3 = fsub fast float %f1, %t1
ret float %t3
; CHECK: @fold9
; CHECK: fsub fast float 0.000000e+00, %f2
}
; Let C3 = C1 + C2. (f1 + C1) + (f2 + C2) => (f1 + f2) + C3 instead of
; "(f1 + C3) + f2" or "(f2 + C3) + f1". Placing constant-addend at the
; top of resulting simplified expression tree may potentially reveal some
; optimization opportunities in the super-expression trees.
;
define float @fold10(float %f1, float %f2) {
%t1 = fadd fast float 2.000000e+00, %f1
%t2 = fsub fast float %f2, 3.000000e+00
%t3 = fadd fast float %t1, %t2
ret float %t3
; CHECK: @fold10
; CHECK: %t3 = fadd fast float %t2, -1.000000e+00
; CHECK: ret float %t3
}
; once cause Crash/miscompilation
define float @fail1(float %f1, float %f2) {
%conv3 = fadd fast float %f1, -1.000000e+00
%add = fadd fast float %conv3, %conv3
%add2 = fadd fast float %add, %conv3
ret float %add2
; CHECK: @fail1
; CHECK: ret
}
define double @fail2(double %f1, double %f2) {
%t1 = fsub fast double %f1, %f2
%t2 = fadd fast double %f1, %f2
%t3 = fsub fast double %t1, %t2
ret double %t3
; CHECK: @fail2
; CHECK: ret
}
; =========================================================================
;
; Testing-cases about fmul begin
;
; =========================================================================
; ((X*C1) + C2) * C3 => (X * (C1*C3)) + (C2*C3) (i.e. distribution)
define float @fmul_distribute1(float %f1) {
%t1 = fmul float %f1, 6.0e+3
%t2 = fadd float %t1, 2.0e+3
%t3 = fmul fast float %t2, 5.0e+3
ret float %t3
; CHECK: @fmul_distribute1
; CHECK: %1 = fmul fast float %f1, 3.000000e+07
; CHECK: %t3 = fadd fast float %1, 1.000000e+07
}
; (X/C1 + C2) * C3 => X/(C1/C3) + C2*C3
define double @fmul_distribute2(double %f1, double %f2) {
%t1 = fdiv double %f1, 3.0e+0
%t2 = fadd double %t1, 5.0e+1
; 0x10000000000000 = DBL_MIN
%t3 = fmul fast double %t2, 0x10000000000000
ret double %t3
; CHECK: @fmul_distribute2
; CHECK: %1 = fdiv fast double %f1, 0x7FE8000000000000
; CHECK: fadd fast double %1, 0x69000000000000
}
; 5.0e-1 * DBL_MIN yields denormal, so "(f1*3.0 + 5.0e-1) * DBL_MIN" cannot
; be simplified into f1 * (3.0*DBL_MIN) + (5.0e-1*DBL_MIN)
define double @fmul_distribute3(double %f1) {
%t1 = fdiv double %f1, 3.0e+0
%t2 = fadd double %t1, 5.0e-1
%t3 = fmul fast double %t2, 0x10000000000000
ret double %t3
; CHECK: @fmul_distribute3
; CHECK: fmul fast double %t2, 0x10000000000000
}
; ((X*C1) + C2) * C3 => (X * (C1*C3)) + (C2*C3) (i.e. distribution)
define float @fmul_distribute4(float %f1) {
%t1 = fmul float %f1, 6.0e+3
%t2 = fsub float 2.0e+3, %t1
%t3 = fmul fast float %t2, 5.0e+3
ret float %t3
; CHECK: @fmul_distribute4
; CHECK: %1 = fmul fast float %f1, 3.000000e+07
; CHECK: %t3 = fsub fast float 1.000000e+07, %1
}
; C1/X * C2 => (C1*C2) / X
define float @fmul2(float %f1) {
%t1 = fdiv float 2.0e+3, %f1
%t3 = fmul fast float %t1, 6.0e+3
ret float %t3
; CHECK: @fmul2
; CHECK: fdiv fast float 1.200000e+07, %f1
}
; X/C1 * C2 => X * (C2/C1) (if C2/C1 is normal Fp)
define float @fmul3(float %f1, float %f2) {
%t1 = fdiv float %f1, 2.0e+3
%t3 = fmul fast float %t1, 6.0e+3
ret float %t3
; CHECK: @fmul3
; CHECK: fmul fast float %f1, 3.000000e+00
}
; Rule "X/C1 * C2 => X * (C2/C1) is not applicable if C2/C1 is either a special
; value of a denormal. The 0x3810000000000000 here take value FLT_MIN
;
define float @fmul4(float %f1, float %f2) {
%t1 = fdiv float %f1, 2.0e+3
%t3 = fmul fast float %t1, 0x3810000000000000
ret float %t3
; CHECK: @fmul4
; CHECK: fmul fast float %t1, 0x3810000000000000
}
; X / C1 * C2 => X / (C2/C1) if C1/C2 is either a special value of a denormal,
; and C2/C1 is a normal value.
;
define float @fmul5(float %f1, float %f2) {
%t1 = fdiv float %f1, 3.0e+0
%t3 = fmul fast float %t1, 0x3810000000000000
ret float %t3
; CHECK: @fmul5
; CHECK: fdiv fast float %f1, 0x47E8000000000000
}
; (X*Y) * X => (X*X) * Y
define float @fmul6(float %f1, float %f2) {
%mul = fmul float %f1, %f2
%mul1 = fmul fast float %mul, %f1
ret float %mul1
; CHECK: @fmul6
; CHECK: fmul fast float %f1, %f1
}
; "(X*Y) * X => (X*X) * Y" is disabled if "X*Y" has multiple uses
define float @fmul7(float %f1, float %f2) {
%mul = fmul float %f1, %f2
%mul1 = fmul fast float %mul, %f1
%add = fadd float %mul1, %mul
ret float %add
; CHECK: @fmul7
; CHECK: fmul fast float %mul, %f1
}
; =========================================================================
;
; Testing-cases about negation
;
; =========================================================================
define float @fneg1(float %f1, float %f2) {
%sub = fsub float -0.000000e+00, %f1
%sub1 = fsub nsz float 0.000000e+00, %f2
%mul = fmul float %sub, %sub1
ret float %mul
; CHECK: @fneg1
; CHECK: fmul float %f1, %f2
}
; =========================================================================
;
; Testing-cases about div
;
; =========================================================================
; X/C1 / C2 => X * (1/(C2*C1))
define float @fdiv1(float %x) {
%div = fdiv float %x, 0x3FF3333340000000
%div1 = fdiv fast float %div, 0x4002666660000000
ret float %div1
; 0x3FF3333340000000 = 1.2f
; 0x4002666660000000 = 2.3f
; 0x3FD7303B60000000 = 0.36231884057971014492
; CHECK: @fdiv1
; CHECK: fmul fast float %x, 0x3FD7303B60000000
}
; X*C1 / C2 => X * (C1/C2)
define float @fdiv2(float %x) {
%mul = fmul float %x, 0x3FF3333340000000
%div1 = fdiv fast float %mul, 0x4002666660000000
ret float %div1
; 0x3FF3333340000000 = 1.2f
; 0x4002666660000000 = 2.3f
; 0x3FE0B21660000000 = 0.52173918485641479492
; CHECK: @fdiv2
; CHECK: fmul fast float %x, 0x3FE0B21660000000
}
; "X/C1 / C2 => X * (1/(C2*C1))" is disabled (for now) is C2/C1 is a denormal
;
define float @fdiv3(float %x) {
%div = fdiv float %x, 0x47EFFFFFE0000000
%div1 = fdiv fast float %div, 0x4002666660000000
ret float %div1
; CHECK: @fdiv3
; CHECK: fdiv float %x, 0x47EFFFFFE0000000
}
; "X*C1 / C2 => X * (C1/C2)" is disabled if C1/C2 is a denormal
define float @fdiv4(float %x) {
%mul = fmul float %x, 0x47EFFFFFE0000000
%div = fdiv float %mul, 0x3FC99999A0000000
ret float %div
; CHECK: @fdiv4
; CHECK: fmul float %x, 0x47EFFFFFE0000000
}
; (X/Y)/Z = > X/(Y*Z)
define float @fdiv5(float %f1, float %f2, float %f3) {
%t1 = fdiv float %f1, %f2
%t2 = fdiv fast float %t1, %f3
ret float %t2
; CHECK: @fdiv5
; CHECK: fmul float %f2, %f3
}
; Z/(X/Y) = > (Z*Y)/X
define float @fdiv6(float %f1, float %f2, float %f3) {
%t1 = fdiv float %f1, %f2
%t2 = fdiv fast float %f3, %t1
ret float %t2
; CHECK: @fdiv6
; CHECK: fmul float %f3, %f2
}
; C1/(X*C2) => (C1/C2) / X
define float @fdiv7(float %x) {
%t1 = fmul float %x, 3.0e0
%t2 = fdiv fast float 15.0e0, %t1
ret float %t2
; CHECK: @fdiv7
; CHECK: fdiv fast float 5.000000e+00, %x
}
; C1/(X/C2) => (C1*C2) / X
define float @fdiv8(float %x) {
%t1 = fdiv float %x, 3.0e0
%t2 = fdiv fast float 15.0e0, %t1
ret float %t2
; CHECK: @fdiv8
; CHECK: fdiv fast float 4.500000e+01, %x
}
; C1/(C2/X) => (C1/C2) * X
define float @fdiv9(float %x) {
%t1 = fdiv float 3.0e0, %x
%t2 = fdiv fast float 15.0e0, %t1
ret float %t2
; CHECK: @fdiv9
; CHECK: fmul fast float %x, 5.000000e+00
}