[LibCallSimplifier] don't get fooled by a fake fmin()

This is similar to the bug/fix:
https://llvm.org/bugs/show_bug.cgi?id=26211
http://reviews.llvm.org/rL258325

The fmin() test case reveals another bug caused by sloppy
code duplication. It will crash without this patch because
fp128 is a valid floating-point type, but we would think
that we had matched a function that used doubles.

The new helper function can be used to replace similar
checks that are used in several other places in this file.

llvm-svn: 258428

1 files changed, 20 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/double-float-shrink-1.ll b/llvm/test/Transforms/InstCombine/double-float-shrink-1.ll
index d3dd0f6746b..5d015bc99ae 100644
--- a/llvm/test/Transforms/InstCombine/double-float-shrink-1.ll
+++ b/llvm/test/Transforms/InstCombine/double-float-shrink-1.ll
@@ -364,6 +364,26 @@ define float @max1(float %a, float %b) {
 ; CHECK-NEXT:  ret
 }
 
+; A function can have a name that matches a common libcall,
+; but with the wrong type(s). Let it be.
+
+define float @fake_fmin(float %a, float %b) {
+  %c = fpext float %a to fp128
+  %d = fpext float %b to fp128
+  %e = call fp128 @fmin(fp128 %c, fp128 %d)
+  %f = fptrunc fp128 %e to float
+  ret float %f
+
+; CHECK-LABEL: fake_fmin(
+; CHECK-NEXT:  %c = fpext float %a to fp128
+; CHECK-NEXT:  %d = fpext float %b to fp128
+; CHECK-NEXT:  %e = call fp128 @fmin(fp128 %c, fp128 %d)
+; CHECK-NEXT:  %f = fptrunc fp128 %e to float
+; CHECK-NEXT:  ret float %f
+}
+
+declare fp128 @fmin(fp128, fp128) ; This is not the 'fmin' you're looking for.
+
 declare double @fmax(double, double)
 
 declare double @tanh(double)