llvm/test/Transforms/InstCombine/log-pow.ll
David Majnemer 14834723b0 Don't remove side effecting instructions due to ConstantFoldInstruction
Just because we can constant fold the result of an instruction does not
imply that we can delete the instruction.  It may have side effects.

This fixes PR28655.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276389 91177308-0d34-0410-b5e6-96231b3b80d8
2016-07-22 04:54:44 +00:00

63 lines
1.9 KiB
LLVM

; RUN: opt < %s -instcombine -S | FileCheck %s
define double @log_pow(double %x, double %y) {
%pow = call fast double @llvm.pow.f64(double %x, double %y)
%call = call fast double @log(double %pow)
ret double %call
}
; CHECK-LABEL: define double @log_pow(
; CHECK-NEXT: %log = call fast double @log(double %x)
; CHECK-NEXT: %mul = fmul fast double %log, %y
; CHECK-NEXT: ret double %mul
define double @log_pow_not_fast(double %x, double %y) {
%pow = call double @llvm.pow.f64(double %x, double %y)
%call = call fast double @log(double %pow)
ret double %call
}
; CHECK-LABEL: define double @log_pow_not_fast(
; CHECK-NEXT: %pow = call double @llvm.pow.f64(double %x, double %y)
; CHECK-NEXT: %call = call fast double @log(double %pow)
; CHECK-NEXT: ret double %call
define double @function_pointer(double ()* %fptr, double %p1) {
%call1 = call double %fptr()
%pow = call double @log(double %call1)
ret double %pow
}
; CHECK-LABEL: @function_pointer
; CHECK-NEXT: %call1 = call double %fptr()
; CHECK-NEXT: %pow = call double @log(double %call1)
; CHECK-NEXT: ret double %pow
define double @log_exp2(double %x) {
%call2 = call fast double @exp2(double %x)
%call3 = call fast double @log(double %call2)
ret double %call3
}
; CHECK-LABEL: @log_exp2
; CHECK-NEXT: %call2 = call fast double @exp2(double %x)
; CHECK-NEXT: %logmul = fmul fast double %x, 0x3FE62E42FEFA39EF
; CHECK-NEXT: ret double %logmul
define double @log_exp2_not_fast(double %x) {
%call2 = call double @exp2(double %x)
%call3 = call fast double @log(double %call2)
ret double %call3
}
; CHECK-LABEL: @log_exp2_not_fast
; CHECK-NEXT: %call2 = call double @exp2(double %x)
; CHECK-NEXT: %call3 = call fast double @log(double %call2)
; CHECK-NEXT: ret double %call3
declare double @log(double) #0
declare double @exp2(double)
declare double @llvm.pow.f64(double, double)
attributes #0 = { nounwind readnone }