[llvm-commits] [llvm] r128626 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineCompares.cpp test/Transforms/InstCombine/fcmp.ll

[Benjamin Kramer]

Author: d0k
Date: Thu Mar 31 05:12:15 2011
New Revision: 128626

URL: http://llvm.org/viewvc/llvm-project?rev=128626&view=rev
Log:
InstCombine: fold fcmp pred (fneg x), C -> fcmp swap(pred) x, -C

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
    llvm/trunk/test/Transforms/InstCombine/fcmp.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=128626&r1=128625&r2=128626&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Thu Mar 31 05:12:15 2011
@@ -2834,6 +2834,14 @@
           return SelectInst::Create(LHSI->getOperand(0), Op1, Op2);
         break;
       }
+      case Instruction::FSub: {
+        // fcmp pred (fneg x), C -> fcmp swap(pred) x, -C
+        Value *Op;
+        if (match(LHSI, m_FNeg(m_Value(Op))))
+          return new FCmpInst(I.getSwappedPredicate(), Op,
+                              ConstantExpr::getFNeg(RHSC));
+        break;
+      }
       case Instruction::Load:
         if (GetElementPtrInst *GEP =
             dyn_cast<GetElementPtrInst>(LHSI->getOperand(0))) {

Modified: llvm/trunk/test/Transforms/InstCombine/fcmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/fcmp.ll?rev=128626&r1=128625&r2=128626&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/fcmp.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/fcmp.ll Thu Mar 31 05:12:15 2011
@@ -32,3 +32,11 @@
 ; CHECK: @test4
 ; CHECK-NEXT: fpext float %a to double
 }
+
+define i1 @test5(float %a) nounwind {
+  %neg = fsub float -0.000000e+00, %a
+  %cmp = fcmp ogt float %neg, 1.000000e+00
+  ret i1 %cmp
+; CHECK: @test5
+; CHECK-NEXT: fcmp olt float %a, -1.0
+}