[llvm] r213231 - Move ashr optimization from InstCombineShift to InstSimplify.

[Suyog Sarda]

Author: suyog
Date: Thu Jul 17 01:28:15 2014
New Revision: 213231

URL: http://llvm.org/viewvc/llvm-project?rev=213231&view=rev
Log:
Move ashr optimization from InstCombineShift to InstSimplify.
Refactor code, no functionality change, test case moved from instcombine to instsimplify.

Differential Revision: http://reviews.llvm.org/D4102
 

Added:
    llvm/trunk/test/Transforms/InstSimplify/ashr-nop.ll
Removed:
    llvm/trunk/test/Transforms/InstCombine/ashr-nop.ll
Modified:
    llvm/trunk/lib/Analysis/InstructionSimplify.cpp
    llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp

Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=213231&r1=213230&r2=213231&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Thu Jul 17 01:28:15 2014
@@ -1346,6 +1346,11 @@ static Value *SimplifyAShrInst(Value *Op
       cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
     return X;
 
+  // Arithmetic shifting an all-sign-bit value is a no-op.
+  unsigned NumSignBits = ComputeNumSignBits(Op0);
+  if (NumSignBits == Op0->getType()->getScalarSizeInBits())
+    return Op0;
+
   return nullptr;
 }
 

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp?rev=213231&r1=213230&r2=213231&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp Thu Jul 17 01:28:15 2014
@@ -815,10 +815,5 @@ Instruction *InstCombiner::visitAShr(Bin
                         APInt::getSignBit(I.getType()->getScalarSizeInBits())))
     return BinaryOperator::CreateLShr(Op0, Op1);
 
-  // Arithmetic shifting an all-sign-bit value is a no-op.
-  unsigned NumSignBits = ComputeNumSignBits(Op0);
-  if (NumSignBits == Op0->getType()->getScalarSizeInBits())
-    return ReplaceInstUsesWith(I, Op0);
-
   return nullptr;
 }

Removed: llvm/trunk/test/Transforms/InstCombine/ashr-nop.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/ashr-nop.ll?rev=213230&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/ashr-nop.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/ashr-nop.ll (removed)
@@ -1,8 +0,0 @@
-; RUN: opt < %s -instcombine -S | not grep ashr
-
-define i32 @foo(i32 %x) {
-  %o = and i32 %x, 1
-  %n = add i32 %o, -1
-  %t = ashr i32 %n, 17
-  ret i32 %t
-}

Added: llvm/trunk/test/Transforms/InstSimplify/ashr-nop.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/ashr-nop.ll?rev=213231&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/ashr-nop.ll (added)
+++ llvm/trunk/test/Transforms/InstSimplify/ashr-nop.ll Thu Jul 17 01:28:15 2014
@@ -0,0 +1,10 @@
+; RUN: opt < %s -instsimplify -S | FileCheck %s
+
+; CHECK-LABEL: @foo
+; CHECK-NOT: ashr
+define i32 @foo(i32 %x) {
+ %o = and i32 %x, 1
+ %n = add i32 %o, -1
+ %t = ashr i32 %n, 17
+ ret i32 %t
+}