rdar://13126763

Fix a bug in DAGCombine. The symptom is mistakenly optimizing expression
"x + x*x" into "x * 3.0".


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174239 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 42 insertions, 0 deletions

diff --git a/test/CodeGen/X86/dagcombine_unsafe_math.ll b/test/CodeGen/X86/dagcombine_unsafe_math.ll
new file mode 100644
index 0000000000..a3221dea5b
--- /dev/null
+++ b/test/CodeGen/X86/dagcombine_unsafe_math.ll
@@ -0,0 +1,42 @@
+; RUN: llc < %s -enable-unsafe-fp-math -mtriple=x86_64-apple-darwin -mcpu=corei7-avx | FileCheck %s 
+
+
+; rdar://13126763
+; Expression "x + x*x" was mistakenly transformed into "x * 3.0f".
+
+define float @test1(float %x) {
+  %t1 = fmul fast float %x, %x
+  %t2 = fadd fast float %t1, %x
+  ret float %t2
+; CHECK: test1
+; CHECK: vaddss
+}
+
+; (x + x) + x => x * 3.0
+define float @test2(float %x) {
+  %t1 = fadd fast float %x, %x
+  %t2 = fadd fast float %t1, %x
+  ret float %t2
+; CHECK: .long  1077936128
+; CHECK: test2
+; CHECK: vmulss LCPI1_0(%rip), %xmm0, %xmm0
+}
+
+; x + (x + x) => x * 3.0
+define float @test3(float %x) {
+  %t1 = fadd fast float %x, %x
+  %t2 = fadd fast float %t1, %x
+  ret float %t2
+; CHECK: .long  1077936128
+; CHECK: test3
+; CHECK: vmulss LCPI2_0(%rip), %xmm0, %xmm0
+}
+
+; (y + x) + x != x * 3.0
+define float @test4(float %x, float %y) {
+  %t1 = fadd fast float %x, %y
+  %t2 = fadd fast float %t1, %x
+  ret float %t2
+; CHECK: test4
+; CHECK: vaddss
+}