From 2ccfbc8b71aa094476cf6a746d6dfd9a2b2a734c Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Thu, 31 Mar 2011 10:11:58 +0000
Subject: [PATCH] InstCombine: fold fcmp (fpext x), (fpext y) -> fcmp x, y.

llvm-svn: 128624
---
 .../Transforms/InstCombine/InstCombineCompares.cpp    |  7 +++++++
 llvm/test/Transforms/InstCombine/fcmp.ll              | 11 +++++++++++
 2 files changed, 18 insertions(+)
 create mode 100644 llvm/test/Transforms/InstCombine/fcmp.ll

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 8787e2ae0e02..698b715fd8b9 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2813,5 +2813,12 @@ Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
       }
   }
 
+  // fcmp (fpext x), (fpext y) -> fcmp x, y
+  if (FPExtInst *LHSExt = dyn_cast<FPExtInst>(Op0))
+    if (FPExtInst *RHSExt = dyn_cast<FPExtInst>(Op1))
+      if (LHSExt->getSrcTy() == RHSExt->getSrcTy())
+        return new FCmpInst(I.getPredicate(), LHSExt->getOperand(0),
+                            RHSExt->getOperand(0));
+
   return Changed ? &I : 0;
 }
diff --git a/llvm/test/Transforms/InstCombine/fcmp.ll b/llvm/test/Transforms/InstCombine/fcmp.ll
new file mode 100644
index 000000000000..bef4855a0ed9
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/fcmp.ll
@@ -0,0 +1,11 @@
+; RUN: opt -S -instcombine < %s | FileCheck %s
+
+define i1 @test1(float %x, float %y) nounwind {
+  %ext1 = fpext float %x to double
+  %ext2 = fpext float %y to double
+  %cmp = fcmp ogt double %ext1, %ext2
+  ret i1 %cmp
+; CHECK: @test1
+; CHECK-NEXT: fcmp ogt float %x, %y
+}
+