Reapply: [InstSimplify] Add support for bitcasts"
This reverts commit r276700 and reapplies r276698.
The relevant clang tests have been updated.
llvm-svn: 276727
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 981fb97..8fde9c7 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -70,6 +70,7 @@
static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned);
static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned);
+static Value *SimplifyBitCastInst(Value *, Type *, const Query &, unsigned);
/// For a boolean type, or a vector of boolean type, return false, or
/// a vector with every element false, as appropriate for the type.
@@ -3810,6 +3811,30 @@
RecursionLimit);
}
+static Value *SimplifyBitCastInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
+ if (auto *C = dyn_cast<Constant>(Op))
+ return ConstantFoldCastOperand(Instruction::BitCast, C, Ty, Q.DL);
+
+ // bitcast x -> x
+ if (Op->getType() == Ty)
+ return Op;
+
+ // bitcast(bitcast x) -> x
+ if (auto *BC = dyn_cast<BitCastInst>(Op))
+ if (BC->getOperand(0)->getType() == Ty)
+ return BC->getOperand(0);
+
+ return nullptr;
+}
+
+Value *llvm::SimplifyBitCastInst(Value *Op, Type *Ty, const DataLayout &DL,
+ const TargetLibraryInfo *TLI,
+ const DominatorTree *DT, AssumptionCache *AC,
+ const Instruction *CxtI) {
+ return ::SimplifyBitCastInst(Op, Ty, Query(DL, TLI, DT, AC, CxtI),
+ RecursionLimit);
+}
+
//=== Helper functions for higher up the class hierarchy.
/// Given operands for a BinaryOperator, see if we can fold the result.
@@ -4280,6 +4305,10 @@
Result =
SimplifyTruncInst(I->getOperand(0), I->getType(), DL, TLI, DT, AC, I);
break;
+ case Instruction::BitCast:
+ Result =
+ SimplifyBitCastInst(I->getOperand(0), I->getType(), DL, TLI, DT, AC, I);
+ break;
}
// In general, it is possible for computeKnownBits to determine all bits in a