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| author | Anders Carlsson <andersca@mac.com> | 2011-03-01 15:05:01 +0000 |
|---|---|---|
| committer | Anders Carlsson <andersca@mac.com> | 2011-03-01 15:05:01 +0000 |
| commit | d70be0b2c199183077626a9e756ecd14b807dd56 (patch) | |
| tree | 5b85f4b5a42437fad9909ea63caaac3099a06c00 /lib/Transforms | |
| parent | 32e20a45e5c838c139ffc5650177842796b5a77d (diff) | |
| download | llvm-d70be0b2c199183077626a9e756ecd14b807dd56.tar.gz llvm-d70be0b2c199183077626a9e756ecd14b807dd56.tar.bz2 llvm-d70be0b2c199183077626a9e756ecd14b807dd56.tar.xz | |
Make InstCombiner::FoldAndOfICmps create a ConstantRange that's the
intersection of the LHS and RHS ConstantRanges and return "false" when
the range is empty.
This simplifies some code and catches some extra cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126744 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms')
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineAndOrXor.cpp | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp index 7986d1aca7..c8545f5dee 100644 --- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -14,6 +14,7 @@ #include "InstCombine.h" #include "llvm/Intrinsics.h" #include "llvm/Analysis/InstructionSimplify.h" +#include "llvm/Support/ConstantRange.h" #include "llvm/Support/PatternMatch.h" using namespace llvm; using namespace PatternMatch; @@ -767,7 +768,17 @@ Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) { LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE || RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE) return 0; - + + // Make a constant range that's the intersection of the two icmp ranges. + // If the intersection is empty, we know that the result is false. + ConstantRange LHSRange = + ConstantRange::makeICmpRegion(LHSCC, LHSCst->getValue()); + ConstantRange RHSRange = + ConstantRange::makeICmpRegion(RHSCC, RHSCst->getValue()); + + if (LHSRange.intersectWith(RHSRange).isEmptySet()) + return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0); + // We can't fold (ugt x, C) & (sgt x, C2). if (!PredicatesFoldable(LHSCC, RHSCC)) return 0; @@ -800,10 +811,6 @@ Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) { case ICmpInst::ICMP_EQ: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); - case ICmpInst::ICMP_EQ: // (X == 13 & X == 15) -> false - case ICmpInst::ICMP_UGT: // (X == 13 & X > 15) -> false - case ICmpInst::ICMP_SGT: // (X == 13 & X > 15) -> false - return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0); case ICmpInst::ICMP_NE: // (X == 13 & X != 15) -> X == 13 case ICmpInst::ICMP_ULT: // (X == 13 & X < 15) -> X == 13 case ICmpInst::ICMP_SLT: // (X == 13 & X < 15) -> X == 13 @@ -851,9 +858,6 @@ Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) { case ICmpInst::ICMP_SLT: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); - case ICmpInst::ICMP_EQ: // (X s< 13 & X == 15) -> false - case ICmpInst::ICMP_SGT: // (X s< 13 & X s> 15) -> false - return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0); case ICmpInst::ICMP_UGT: // (X s< 13 & X u> 15) -> no change break; case ICmpInst::ICMP_NE: // (X s< 13 & X != 15) -> X < 13 |