[llvm-commits] [llvm] r153452 - in /llvm/trunk: lib/Analysis/InstructionSimplify.cpp lib/Analysis/ValueTracking.cpp test/Transforms/InstSimplify/pr12251.ll

[Chad Rosier]

Author: mcrosier
Date: Mon Mar 26 13:07:14 2012
New Revision: 153452

URL: http://llvm.org/viewvc/llvm-project?rev=153452&view=rev
Log:
Revert r153423 as this is causing failures on our internal nightly testers.

Original commit message:
Use the new range metadata in computeMaskedBits and add a new optimization to
instruction simplify that lets us remove an and when loading a boolean value.

Removed:
    llvm/trunk/test/Transforms/InstSimplify/pr12251.ll
Modified:
    llvm/trunk/lib/Analysis/InstructionSimplify.cpp
    llvm/trunk/lib/Analysis/ValueTracking.cpp

Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=153452&r1=153451&r2=153452&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Mon Mar 26 13:07:14 2012
@@ -1370,21 +1370,6 @@
       return Op1;
   }
 
-  unsigned Bitwidth = Op1->getType()->getScalarSizeInBits();
-  APInt DemandedMask = APInt::getAllOnesValue(Bitwidth);
-  APInt KnownZero0 = APInt::getNullValue(Bitwidth);
-  APInt KnownOne0 = APInt::getNullValue(Bitwidth);
-  ComputeMaskedBits(Op0, DemandedMask, KnownZero0, KnownOne0);
-  APInt KnownZero1 = APInt::getNullValue(Bitwidth);
-  APInt KnownOne1 = APInt::getNullValue(Bitwidth);
-  ComputeMaskedBits(Op1, DemandedMask, KnownZero1, KnownOne1);
-
-  if ((KnownZero0 | KnownOne1).isAllOnesValue())
-    return Op0;
-
-  if ((KnownZero1 | KnownOne0).isAllOnesValue())
-    return Op1;
-
   // Try some generic simplifications for associative operations.
   if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
                                           MaxRecurse))

Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=153452&r1=153451&r2=153452&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Mon Mar 26 13:07:14 2012
@@ -20,10 +20,8 @@
 #include "llvm/GlobalAlias.h"
 #include "llvm/IntrinsicInst.h"
 #include "llvm/LLVMContext.h"
-#include "llvm/Metadata.h"
 #include "llvm/Operator.h"
 #include "llvm/Target/TargetData.h"
-#include "llvm/Support/ConstantRange.h"
 #include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/PatternMatch.h"
@@ -197,26 +195,6 @@
     KnownOne.setBit(BitWidth - 1);
 }
 
-static void computeMaskedBitsLoad(const MDNode &Ranges, const APInt &Mask,
-                                  APInt &KnownZero) {
-  unsigned BitWidth = Mask.getBitWidth();
-  unsigned NumRanges = Ranges.getNumOperands() / 2;
-  assert(NumRanges >= 1);
-
-  // Use the high end of the ranges to find leading zeros.
-  unsigned MinLeadingZeros = BitWidth;
-  for (unsigned i = 0; i < NumRanges; ++i) {
-    ConstantInt *Lower = cast<ConstantInt>(Ranges.getOperand(2*i + 0));
-    ConstantInt *Upper = cast<ConstantInt>(Ranges.getOperand(2*i + 1));
-    ConstantRange Range(Lower->getValue(), Upper->getValue());
-    if (Range.isWrappedSet())
-      MinLeadingZeros = 0; // -1 has no zeros
-    unsigned LeadingZeros = (Upper->getValue() - 1).countLeadingZeros();
-    MinLeadingZeros = std::min(LeadingZeros, MinLeadingZeros);
-  }
-
-  KnownZero = Mask & APInt::getHighBitsSet(BitWidth, MinLeadingZeros);
-}
 /// ComputeMaskedBits - Determine which of the bits specified in Mask are
 /// known to be either zero or one and return them in the KnownZero/KnownOne
 /// bit sets.  This code only analyzes bits in Mask, in order to short-circuit
@@ -337,10 +315,6 @@
   APInt KnownZero2(KnownZero), KnownOne2(KnownOne);
   switch (I->getOpcode()) {
   default: break;
-  case Instruction::Load:
-    if (MDNode *MD = cast<LoadInst>(I)->getMetadata(LLVMContext::MD_range))
-      computeMaskedBitsLoad(*MD, Mask, KnownZero);
-    return;
   case Instruction::And: {
     // If either the LHS or the RHS are Zero, the result is zero.
     ComputeMaskedBits(I->getOperand(1), Mask, KnownZero, KnownOne, TD, Depth+1);

Removed: llvm/trunk/test/Transforms/InstSimplify/pr12251.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/pr12251.ll?rev=153451&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/pr12251.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/pr12251.ll (removed)
@@ -1,15 +0,0 @@
-; RUN: opt < %s -instsimplify -S | FileCheck %s
-
-define zeroext i1 @_Z3fooPb(i8* nocapture %x) {
-entry:
-  %a = load i8* %x, align 1, !range !0
-  %b = and i8 %a, 1
-  %tobool = icmp ne i8 %b, 0
-  ret i1 %tobool
-}
-
-; CHECK: %a = load i8* %x, align 1, !range !0
-; CHECK-NEXT: %tobool = icmp ne i8 %a, 0
-; CHECK-NEXT: ret i1 %tobool
-
-!0 = metadata !{i8 0, i8 2}