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22f3b9faac
added to the FSub version. However, the original version of this xform guarded
against doing this for floating point (!Op0->getType()->isFPOrFPVector()).
This is causing LLVM to perform incorrect xforms for code like:
void func(double *rhi, double *rlo, double xh, double xl, double yh, double yl){
double mh, ml;
double c = 134217729.0;
double up, u1, u2, vp, v1, v2;
up = xh*c;
u1 = (xh - up) + up;
u2 = xh - u1;
vp = yh*c;
v1 = (yh - vp) + vp;
v2 = yh - v1;
mh = xh*yh;
ml = (((u1*v1 - mh) + (u1*v2)) + (u2*v1)) + (u2*v2);
ml += xh*yl + xl*yh;
*rhi = mh + ml;
*rlo = (mh - (*rhi)) + ml;
}
The last line was optimized away, but rl is intended to be the difference
between the infinitely precise result of mh + ml and after it has been rounded
to double precision.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93369 91177308-0d34-0410-b5e6-96231b3b80d8
40 lines
2.2 KiB
LLVM
40 lines
2.2 KiB
LLVM
; RUN: opt < %s -instcombine -S | FileCheck %s
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; <rdar://problem/7530098>
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define void @func(double* %rhi, double* %rlo, double %xh, double %xl, double %yh, double %yl) nounwind ssp {
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entry:
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%"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
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%tmp = fmul double %xh, 0x41A0000002000000 ; <double> [#uses=2]
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%tmp1 = fsub double %xh, %tmp ; <double> [#uses=1]
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%tmp2 = fadd double %tmp1, %tmp ; <double> [#uses=3]
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%tmp3 = fsub double %xh, %tmp2 ; <double> [#uses=2]
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%tmp4 = fmul double %yh, 0x41A0000002000000 ; <double> [#uses=2]
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%tmp5 = fsub double %yh, %tmp4 ; <double> [#uses=1]
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%tmp6 = fadd double %tmp5, %tmp4 ; <double> [#uses=3]
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%tmp7 = fsub double %yh, %tmp6 ; <double> [#uses=2]
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%tmp8 = fmul double %xh, %yh ; <double> [#uses=3]
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%tmp9 = fmul double %tmp2, %tmp6 ; <double> [#uses=1]
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%tmp10 = fsub double %tmp9, %tmp8 ; <double> [#uses=1]
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%tmp11 = fmul double %tmp2, %tmp7 ; <double> [#uses=1]
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%tmp12 = fadd double %tmp10, %tmp11 ; <double> [#uses=1]
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%tmp13 = fmul double %tmp3, %tmp6 ; <double> [#uses=1]
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%tmp14 = fadd double %tmp12, %tmp13 ; <double> [#uses=1]
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%tmp15 = fmul double %tmp3, %tmp7 ; <double> [#uses=1]
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%tmp16 = fadd double %tmp14, %tmp15 ; <double> [#uses=1]
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%tmp17 = fmul double %xh, %yl ; <double> [#uses=1]
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%tmp18 = fmul double %xl, %yh ; <double> [#uses=1]
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%tmp19 = fadd double %tmp17, %tmp18 ; <double> [#uses=1]
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%tmp20 = fadd double %tmp19, %tmp16 ; <double> [#uses=2]
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%tmp21 = fadd double %tmp8, %tmp20 ; <double> [#uses=1]
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store double %tmp21, double* %rhi, align 8
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%tmp22 = load double* %rhi, align 8 ; <double> [#uses=1]
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%tmp23 = fsub double %tmp8, %tmp22 ; <double> [#uses=1]
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%tmp24 = fadd double %tmp23, %tmp20 ; <double> [#uses=1]
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; CHECK: %tmp23 = fsub double %tmp8, %tmp21
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; CHECK: %tmp24 = fadd double %tmp23, %tmp20
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store double %tmp24, double* %rlo, align 8
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ret void
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}
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