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Revert r146822 at Pete Cooper's request as it broke clang self hosting.

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Hope I did this correctly :)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146834 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Kevin Enderby
2011-12-17 19:48:52 +00:00
parent ab44d3cf49
commit 67005b311c
2 changed files with 0 additions and 194 deletions
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42
lib/Transforms/Utils/SimplifyCFG.cpp
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@@ -12,7 +12,6 @@
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "simplifycfg"
#include "llvm/Transforms/Utils/CmpInstAnalysis.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Constants.h"
#include "llvm/Instructions.h"
@@ -1703,47 +1702,6 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI) {
}
}
// Treat "if (cond1) { if (cond2) {} }" as "cond1 & cond2" and fold.
// This gives us the value of what cond2 is given cond1 is already known to
// be true.
if (ICmpInst *LHS = dyn_cast<ICmpInst>(PBI->getCondition())) {
if (ICmpInst *RHS = dyn_cast<ICmpInst>(BI->getCondition())) {
ICmpInst::Predicate LHSCC = LHS->getPredicate(),
RHSCC = RHS->getPredicate();
if (PredicatesFoldable(LHSCC, RHSCC)) {
if (LHS->getOperand(0) == RHS->getOperand(1) &&
LHS->getOperand(1) == RHS->getOperand(0))
LHS->swapOperands();
if (LHS->getOperand(0) == RHS->getOperand(0) &&
LHS->getOperand(1) == RHS->getOperand(1) &&
BB->getSinglePredecessor()) {
Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
bool CondIsTrue = PBI->getSuccessor(0) == BB;
unsigned LHSCode = getICmpCode(LHS, !CondIsTrue);
unsigned RHSCode = getICmpCode(RHS);
unsigned Code = LHSCode & RHSCode;
Value *ConstantCondition = NULL;
// If the resultant code is the same as the LHS code then as that
// code is known to be true we can make RHS now be true.
if (Code == LHSCode)
ConstantCondition = ConstantInt::get(
CmpInst::makeCmpResultType(LHS->getType()), 1);
else {
bool isSigned = LHS->isSigned() || RHS->isSigned();
CmpInst::Predicate IgnoredNewPred;
ConstantCondition = getICmpValue(isSigned, Code, Op0, Op1,
IgnoredNewPred);
}
if (ConstantCondition) {
RHS->replaceAllUsesWith(ConstantCondition);
return true;
}
}
}
}
}
// If this is a conditional branch in an empty block, and if any
// predecessors is a conditional branch to one of our destinations,
// fold the conditions into logical ops and one cond br.