[llvm-commits] [llvm] r51560 - in /llvm/trunk: lib/Analysis/ScalarEvolution.cpp test/Analysis/ScalarEvolution/2008-05-25-NegativeStepToZero.ll

[Nick Lewycky]

Author: nicholas
Date: Sun May 25 18:43:32 2008
New Revision: 51560

URL: http://llvm.org/viewvc/llvm-project?rev=51560&view=rev
Log:
Don't treat values as signed when looking at loop steppings in HowForToNonZero.

Added:
    llvm/trunk/test/Analysis/ScalarEvolution/2008-05-25-NegativeStepToZero.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=51560&r1=51559&r2=51560&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Sun May 25 18:43:32 2008
@@ -2548,9 +2548,9 @@
       if (SCEVConstant *StartC = dyn_cast<SCEVConstant>(Start)) {
         ConstantInt *StartCC = StartC->getValue();
         Constant *StartNegC = ConstantExpr::getNeg(StartCC);
-        Constant *Rem = ConstantExpr::getSRem(StartNegC, StepC->getValue());
+        Constant *Rem = ConstantExpr::getURem(StartNegC, StepC->getValue());
         if (Rem->isNullValue()) {
-          Constant *Result =ConstantExpr::getSDiv(StartNegC,StepC->getValue());
+          Constant *Result = ConstantExpr::getUDiv(StartNegC,StepC->getValue());
           return SE.getUnknown(Result);
         }
       }

Added: llvm/trunk/test/Analysis/ScalarEvolution/2008-05-25-NegativeStepToZero.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/2008-05-25-NegativeStepToZero.ll?rev=51560&view=auto

==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/2008-05-25-NegativeStepToZero.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/2008-05-25-NegativeStepToZero.ll Sun May 25 18:43:32 2008
@@ -0,0 +1,20 @@
+; RUN: llvm-as < %s | opt -analyze -scalar-evolution | grep {61 iterations}
+
+define i32 @func_6() nounwind  {
+entry:
+	br label %bb5
+
+bb:		; preds = %bb5
+	%tmp2 = add i32 %i.0, 1		; <i32> [#uses=1]
+	%tmp4 = add i8 %x.0, -4		; <i8> [#uses=1]
+	br label %bb5
+
+bb5:		; preds = %bb, %entry
+	%x.0 = phi i8 [ 0, %entry ], [ %tmp4, %bb ]		; <i8> [#uses=2]
+	%i.0 = phi i32 [ 0, %entry ], [ %tmp2, %bb ]		; <i32> [#uses=2]
+	%tmp7 = icmp eq i8 %x.0, 12		; <i1> [#uses=1]
+	br i1 %tmp7, label %return, label %bb
+
+return:		; preds = %bb5
+	ret i32 %i.0
+}