[PATCH] Make InlineCost check for constant foldable floating point compares

[Matt Arsenault]

Hi chandlerc,

Currently it only checks icmp

http://llvm-reviews.chandlerc.com/D1182

Files:
  lib/Analysis/IPA/InlineCost.cpp
  test/Transforms/Inline/inline_constprop.ll

Index: lib/Analysis/IPA/InlineCost.cpp
===================================================================
--- lib/Analysis/IPA/InlineCost.cpp
+++ lib/Analysis/IPA/InlineCost.cpp
@@ -124,7 +124,7 @@
   bool visitIntToPtr(IntToPtrInst &I);
   bool visitCastInst(CastInst &I);
   bool visitUnaryInstruction(UnaryInstruction &I);
-  bool visitICmp(ICmpInst &I);
+  bool visitCmpInst(CmpInst &I);
   bool visitSub(BinaryOperator &I);
   bool visitBinaryOperator(BinaryOperator &I);
   bool visitLoad(LoadInst &I);
@@ -490,21 +490,25 @@
   return false;
 }
 
-bool CallAnalyzer::visitICmp(ICmpInst &I) {
+bool CallAnalyzer::visitCmpInst(CmpInst &I) {
   Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
   // First try to handle simplified comparisons.
   if (!isa<Constant>(LHS))
     if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS))
       LHS = SimpleLHS;
   if (!isa<Constant>(RHS))
     if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
       RHS = SimpleRHS;
-  if (Constant *CLHS = dyn_cast<Constant>(LHS))
+  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
     if (Constant *CRHS = dyn_cast<Constant>(RHS))
-      if (Constant *C = ConstantExpr::getICmp(I.getPredicate(), CLHS, CRHS)) {
+      if (Constant *C = ConstantExpr::getCompare(I.getPredicate(), CLHS, CRHS)) {
         SimplifiedValues[&I] = C;
         return true;
       }
+  }
+
+  if (I.getOpcode() == Instruction::FCmp)
+    return false;
 
   // Otherwise look for a comparison between constant offset pointers with
   // a common base.
Index: test/Transforms/Inline/inline_constprop.ll
===================================================================
--- test/Transforms/Inline/inline_constprop.ll
+++ test/Transforms/Inline/inline_constprop.ll
@@ -187,6 +187,37 @@
   ret i64 %y8
 }
 
+define float @caller6() {
+; Check that we can constant-prop through fcmp instructions
+;
+; CHECK-LABEL: @caller6(
+; CHECK-NOT: call
+; CHECK: ret
+  %x = call float @callee6(float 42.0)
+  ret float %x
+}
+
+define float @callee6(float %x) {
+  %icmp = fcmp ugt float %x, 42.0
+  br i1 %icmp, label %bb.true, label %bb.false
+
+bb.true:
+  ; This block musn't be counted in the inline cost.
+  %x1 = fadd float %x, 1.0
+  %x2 = fadd float %x1, 1.0
+  %x3 = fadd float %x2, 1.0
+  %x4 = fadd float %x3, 1.0
+  %x5 = fadd float %x4, 1.0
+  %x6 = fadd float %x5, 1.0
+  %x7 = fadd float %x6, 1.0
+  %x8 = fadd float %x7, 1.0
+  ret float %x8
+
+bb.false:
+  ret float %x
+}
+
+
 
 define i32 @PR13412.main() {
 ; This is a somewhat complicated three layer subprogram that was reported to
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