[llvm-commits] [llvm] r143719 - in /llvm/trunk: lib/Analysis/InstructionSimplify.cpp test/Transforms/InstSimplify/undef.ll

[Dan Gohman]

Author: djg
Date: Fri Nov  4 13:32:42 2011
New Revision: 143719

URL: http://llvm.org/viewvc/llvm-project?rev=143719&view=rev
Log:
Teach instsimplify to simplify calls to undef.

Modified:
    llvm/trunk/lib/Analysis/InstructionSimplify.cpp
    llvm/trunk/test/Transforms/InstSimplify/undef.ll

Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=143719&r1=143718&r2=143719&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Fri Nov  4 13:32:42 2011
@@ -2474,6 +2474,14 @@
   return ::SimplifyCmpInst(Predicate, LHS, RHS, TD, DT, RecursionLimit);
 }
 
+static Value *SimplifyCallInst(CallInst *CI) {
+  // call undef -> undef
+  if (isa<UndefValue>(CI->getCalledValue()))
+    return UndefValue::get(CI->getType());
+
+  return 0;
+}
+
 /// SimplifyInstruction - See if we can compute a simplified version of this
 /// instruction.  If not, this returns null.
 Value *llvm::SimplifyInstruction(Instruction *I, const TargetData *TD,
@@ -2569,6 +2577,9 @@
   case Instruction::PHI:
     Result = SimplifyPHINode(cast<PHINode>(I), DT);
     break;
+  case Instruction::Call:
+    Result = SimplifyCallInst(cast<CallInst>(I));
+    break;
   }
 
   /// If called on unreachable code, the above logic may report that the

Modified: llvm/trunk/test/Transforms/InstSimplify/undef.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/undef.ll?rev=143719&r1=143718&r2=143719&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/undef.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/undef.ll Fri Nov  4 13:32:42 2011
@@ -125,3 +125,10 @@
   %r = select i1 undef, i64 undef, i64 %a
   ret i64 %r
 }
+
+; @test18
+; CHECK: ret i64 undef
+define i64 @test18(i64 %a) {
+  %r = call i64 (i64)* undef(i64 %a)
+  ret i64 %r
+}