[llvm-commits] [llvm] r89955 - in /llvm/trunk: lib/Analysis/BasicAliasAnalysis.cpp test/Analysis/BasicAA/gep-alias.ll

[Chris Lattner]

Author: lattner
Date: Thu Nov 26 11:00:01 2009
New Revision: 89955

URL: http://llvm.org/viewvc/llvm-project?rev=89955&view=rev
Log:
teach GetLinearExpression to be a bit more aggressive.

Modified:
    llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
    llvm/trunk/test/Analysis/BasicAA/gep-alias.ll

Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp?rev=89955&r1=89954&r2=89955&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Thu Nov 26 11:00:01 2009
@@ -400,7 +400,16 @@
         V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, TD);
         Offset += RHSC->getValue();
         return V;
-      // TODO: SHL, MUL.
+      case Instruction::Mul:
+        V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, TD);
+        Offset *= RHSC->getValue();
+        Scale *= RHSC->getValue();
+        return V;
+      case Instruction::Shl:
+        V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, TD);
+        Offset <<= RHSC->getValue().getLimitedValue();
+        Scale <<= RHSC->getValue().getLimitedValue();
+        return V;
       }
     }
   }

Modified: llvm/trunk/test/Analysis/BasicAA/gep-alias.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/gep-alias.ll?rev=89955&r1=89954&r2=89955&view=diff

==============================================================================
--- llvm/trunk/test/Analysis/BasicAA/gep-alias.ll (original)
+++ llvm/trunk/test/Analysis/BasicAA/gep-alias.ll Thu Nov 26 11:00:01 2009
@@ -101,3 +101,18 @@
 ; CHECK: ret i32 0
 }
 
+; P[1] != P[i*4]
+define i32 @test7(i32* %p, i64 %i) {
+  %pi = getelementptr i32* %p, i64 1
+  %i.next = shl i64 %i, 2
+  %pi.next = getelementptr i32* %p, i64 %i.next
+  %x = load i32* %pi
+  store i32 42, i32* %pi.next
+  %y = load i32* %pi
+  %z = sub i32 %x, %y
+  ret i32 %z
+; CHECK: @test7
+; CHECK: ret i32 0
+}
+
+