[llvm-commits] [llvm] r123832 - in /llvm/trunk: lib/Analysis/ScalarEvolution.cpp test/Analysis/ScalarEvolution/fold.ll

[Nick Lewycky]

Author: nicholas
Date: Wed Jan 19 09:56:12 2011
New Revision: 123832

URL: http://llvm.org/viewvc/llvm-project?rev=123832&view=rev
Log:
Add a missing SCEV simplification sext(zext x) --> zext x.

Added:
    llvm/trunk/test/Analysis/ScalarEvolution/fold.ll
Modified:
    llvm/trunk/lib/Analysis/ScalarEvolution.cpp

Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=123832&r1=123831&r2=123832&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Wed Jan 19 09:56:12 2011
@@ -994,6 +994,10 @@
   if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op))
     return getSignExtendExpr(SS->getOperand(), Ty);
 
+  // sext(zext(x)) --> zext(x)
+  if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
+    return getZeroExtendExpr(SZ->getOperand(), Ty);
+
   // Before doing any expensive analysis, check to see if we've already
   // computed a SCEV for this Op and Ty.
   FoldingSetNodeID ID;

Added: llvm/trunk/test/Analysis/ScalarEvolution/fold.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/fold.ll?rev=123832&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/fold.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/fold.ll Wed Jan 19 09:56:12 2011
@@ -0,0 +1,8 @@
+; RUN: opt -analyze -scalar-evolution %s -S | FileCheck %s
+
+define i16 @test(i8 %x) {
+  %A = zext i8 %x to i12
+  %B = sext i12 %A to i16
+; CHECK: zext i8 %x to i16
+  ret i16 %B
+}