constant fold nasty constant expressions formed by llvm-gcc,
wrapping up PR3351.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92410 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index eaf90d0..194caba 100644
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -718,14 +718,13 @@
switch (Opcode) {
default: return 0;
+ case Instruction::ICmp:
+ case Instruction::FCmp: assert(0 && "Invalid for compares");
case Instruction::Call:
if (Function *F = dyn_cast<Function>(Ops[0]))
if (canConstantFoldCallTo(F))
return ConstantFoldCall(F, Ops+1, NumOps-1);
return 0;
- case Instruction::ICmp:
- case Instruction::FCmp:
- llvm_unreachable("This function is invalid for compares: no predicate specified");
case Instruction::PtrToInt:
// If the input is a inttoptr, eliminate the pair. This requires knowing
// the width of a pointer, so it can't be done in ConstantExpr::getCast.
@@ -877,6 +876,20 @@
CE1->getOperand(0), TD);
}
}
+
+ // icmp eq (or x, y), 0 -> (icmp eq x, 0) & (icmp eq y, 0)
+ // icmp ne (or x, y), 0 -> (icmp ne x, 0) | (icmp ne y, 0)
+ if ((Predicate == ICmpInst::ICMP_EQ || Predicate == ICmpInst::ICMP_NE) &&
+ CE0->getOpcode() == Instruction::Or && Ops1->isNullValue()) {
+ Constant *LHS =
+ ConstantFoldCompareInstOperands(Predicate, CE0->getOperand(0), Ops1,TD);
+ Constant *RHS =
+ ConstantFoldCompareInstOperands(Predicate, CE0->getOperand(1), Ops1,TD);
+ unsigned OpC =
+ Predicate == ICmpInst::ICMP_EQ ? Instruction::And : Instruction::Or;
+ Constant *Ops[] = { LHS, RHS };
+ return ConstantFoldInstOperands(OpC, LHS->getType(), Ops, 2, TD);
+ }
}
return ConstantExpr::getCompare(Predicate, Ops0, Ops1);