[x86] add test to show missing optimization

This should make it clearer how this proposed patch:
http://reviews.llvm.org/D11393
...will change codegen.

llvm-svn: 262875

diff --git a/llvm/test/CodeGen/X86/fp-une-cmp.ll b/llvm/test/CodeGen/X86/fp-une-cmp.ll
index e0b8f61..9fab5c4 100644 (file)
--- a/llvm/test/CodeGen/X86/fp-une-cmp.ll
+++ b/llvm/test/CodeGen/X86/fp-une-cmp.ll
@@ -48,3 +48,34 @@ bb2:
   ret double %phi
 }
 
+; FIXME: With branch weights indicated, bb2 should be placed ahead of bb1.
+
+define double @profile_metadata(double %x, double %y) {
+; CHECK-LABEL: profile_metadata:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    mulsd %xmm1, %xmm0
+; CHECK-NEXT:    xorpd %xmm1, %xmm1
+; CHECK-NEXT:    ucomisd %xmm1, %xmm0
+; CHECK-NEXT:    jne .LBB1_1
+; CHECK-NEXT:    jnp .LBB1_2
+; CHECK-NEXT:  .LBB1_1: # %bb1
+; CHECK-NEXT:    addsd {{.*}}(%rip), %xmm0
+; CHECK-NEXT:  .LBB1_2: # %bb2
+; CHECK-NEXT:    retq
+
+entry:
+  %mul = fmul double %x, %y
+  %cmp = fcmp une double %mul, 0.000000e+00
+  br i1 %cmp, label %bb1, label %bb2, !prof !1
+
+bb1:
+  %add = fadd double %mul, -1.000000e+00
+  br label %bb2
+
+bb2:
+  %phi = phi double [ %add, %bb1 ], [ %mul, %entry ]
+  ret double %phi
+}
+
+!1 = !{!"branch_weights", i32 1, i32 1000}
+