[DAG] add test to show FMF mismatch between IR and DAG; NFC

D45710 proposes to change this, but we have no test coverage 
for the first step in this process.

llvm-svn: 331271

1 files changed, 32 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/fmf-propagation.ll b/llvm/test/CodeGen/X86/fmf-propagation.ll
new file mode 100644
index 00000000000..294a2952c76
--- /dev/null
+++ b/llvm/test/CodeGen/X86/fmf-propagation.ll
@@ -0,0 +1,32 @@
+; REQUIRES: asserts
+; RUN: llc -mtriple=x86_64-unknown-unknown -debug-only=isel < %s -o /dev/null 2>&1 | FileCheck %s
+
+; This tests the propagation of fast-math-flags from IR instructions to SDNodeFlags.
+
+; FIXME: 'afn' and 'reassoc' were dropped. With 'fast', 'reassoc' got renamed to 'unsafe'.
+
+; CHECK-LABEL: Initial selection DAG: %bb.0 'fmf_transfer:'
+
+; CHECK:         t5: f32 = fadd nsz t2, t4
+; CHECK-NEXT:    t6: f32 = fadd arcp t5, t4
+; CHECK-NEXT:    t7: f32 = fadd nnan t6, t4
+; CHECK-NEXT:    t8: f32 = fadd ninf t7, t4
+; CHECK-NEXT:    t9: f32 = fadd contract t8, t4
+; CHECK-NEXT:    t10: f32 = fadd t9, t4
+; CHECK-NEXT:    t11: f32 = fadd t10, t4
+; CHECK-NEXT:    t12: f32 = fadd unsafe nnan ninf nsz arcp contract t11, t4
+
+; CHECK: Optimized lowered selection DAG: %bb.0 'fmf_transfer:'
+
+define float @fmf_transfer(float %x, float %y) {
+  %f1 = fadd nsz float %x, %y
+  %f2 = fadd arcp float %f1, %y
+  %f3 = fadd nnan float %f2, %y
+  %f4 = fadd ninf float %f3, %y
+  %f5 = fadd contract float %f4, %y
+  %f6 = fadd afn float %f5, %y
+  %f7 = fadd reassoc float %f6, %y
+  %f8 = fadd fast float %f7, %y
+  ret float %f8
+}
+