Convert sqrt functions into sqrt instructions when -ffast-math is in effect.

When -ffast-math is in effect (on Linux, at least), clang defines
__FINITE_MATH_ONLY__ > 0 when including <math.h>. This causes the
preprocessor to include <bits/math-finite.h>, which renames the sqrt functions.
For instance, "sqrt" is renamed as "__sqrt_finite". 

This patch adds the 3 new names in such a way that they will be treated
as equivalent to their respective original names.





git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182739 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 60 insertions, 0 deletions

diff --git a/test/CodeGen/X86/sqrt-fastmath.ll b/test/CodeGen/X86/sqrt-fastmath.ll
new file mode 100644
index 0000000000..9b5179efa4
--- /dev/null
+++ b/test/CodeGen/X86/sqrt-fastmath.ll
@@ -0,0 +1,60 @@
+; RUN: llc < %s -mcpu=core2 | FileCheck %s
+
+; generated using "clang -S -O2 -ffast-math -emit-llvm sqrt.c" from
+; #include <math.h>
+; 
+; double fd(double d){
+;   return sqrt(d);
+; }
+; 
+; float ff(float f){
+;   return sqrtf(f);
+; }
+; 
+; long double fld(long double ld){
+;   return sqrtl(ld);
+; }
+;
+; Tests conversion of sqrt function calls into sqrt instructions when
+; -ffast-math is in effect.
+
+; ModuleID = 'sqrt.c'
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: nounwind readnone uwtable
+define double @fd(double %d) #0 {
+entry:
+; CHECK: sqrtsd
+  %call = tail call double @__sqrt_finite(double %d) #2
+  ret double %call
+}
+
+; Function Attrs: nounwind readnone
+declare double @__sqrt_finite(double) #1
+
+; Function Attrs: nounwind readnone uwtable
+define float @ff(float %f) #0 {
+entry:
+; CHECK: sqrtss
+  %call = tail call float @__sqrtf_finite(float %f) #2
+  ret float %call
+}
+
+; Function Attrs: nounwind readnone
+declare float @__sqrtf_finite(float) #1
+
+; Function Attrs: nounwind readnone uwtable
+define x86_fp80 @fld(x86_fp80 %ld) #0 {
+entry:
+; CHECK: fsqrt
+  %call = tail call x86_fp80 @__sqrtl_finite(x86_fp80 %ld) #2
+  ret x86_fp80 %call
+}
+
+; Function Attrs: nounwind readnone
+declare x86_fp80 @__sqrtl_finite(x86_fp80) #1
+
+attributes #0 = { nounwind readnone uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-frame-pointer-elim-non-leaf"="false" "no-infs-fp-math"="true" "no-nans-fp-math"="true" "unsafe-fp-math"="true" "use-soft-float"="false" }
+attributes #1 = { nounwind readnone "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-frame-pointer-elim-non-leaf"="false" "no-infs-fp-math"="true" "no-nans-fp-math"="true" "unsafe-fp-math"="true" "use-soft-float"="false" }
+attributes #2 = { nounwind readnone }