libcalls-fast-math-inf-loop.ll
2.65 KB
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; RUN: opt -S -instcombine -o - %s | FileCheck %s
; Test that fast math lib call simplification of double math function to float
; equivalent doesn't occur when the calling function matches the float
; equivalent math function. Otherwise this can cause the generation of infinite
; loops when compiled with -O2/3 and fast math.
; Test case C source:
;
; extern double exp(double x);
; inline float expf(float x) { return (float) exp((double) x); }
; float fn(float f) { return expf(f); }
;
; IR generated with command:
;
; clang -cc1 -O2 -ffast-math -emit-llvm -disable-llvm-passes -triple x86_64-unknown-unknown -o - <srcfile>
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-unknown"
; Function Attrs: nounwind
define float @fn(float %f) #0 {
; CHECK: define float @fn(
; CHECK: call fast float @expf(
%f.addr = alloca float, align 4
store float %f, float* %f.addr, align 4, !tbaa !1
%1 = load float, float* %f.addr, align 4, !tbaa !1
%call = call fast float @expf(float %1) #3
ret float %call
}
; Function Attrs: inlinehint nounwind readnone
define available_externally float @expf(float %x) #1 {
; CHECK: define available_externally float @expf(
; CHECK: fpext float
; CHECK: call fast double @exp(
; CHECK: fptrunc double
%x.addr = alloca float, align 4
store float %x, float* %x.addr, align 4, !tbaa !1
%1 = load float, float* %x.addr, align 4, !tbaa !1
%conv = fpext float %1 to double
%call = call fast double @exp(double %conv) #3
%conv1 = fptrunc double %call to float
ret float %conv1
}
; Function Attrs: nounwind readnone
declare double @exp(double) #2
attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "frame-pointer"="none" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-features"="+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { inlinehint nounwind readnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "frame-pointer"="none" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-features"="+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #2 = { nounwind readnone }
!llvm.ident = !{!0}
!0 = !{!"clang version 5.0.0"}
!1 = !{!2, !2, i64 0}
!2 = !{!"float", !3, i64 0}
!3 = !{!"omnipotent char", !4, i64 0}
!4 = !{!"Simple C/C++ TBAA"}