[llvm-commits] [llvm] r94993 - in /llvm/trunk: lib/VMCore/ConstantFold.cpp test/Transforms/ConstProp/basictest.ll
Chris Lattner
sabre at nondot.org
Mon Feb 1 11:35:08 PST 2010
Author: lattner
Date: Mon Feb 1 13:35:08 2010
New Revision: 94993
URL: http://llvm.org/viewvc/llvm-project?rev=94993&view=rev
Log:
fix PR6197 - infinite recursion in ipsccp due to block addresses
evaluateICmpRelation wasn't handling blockaddress.
Modified:
llvm/trunk/lib/VMCore/ConstantFold.cpp
llvm/trunk/test/Transforms/ConstProp/basictest.ll
Modified: llvm/trunk/lib/VMCore/ConstantFold.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/ConstantFold.cpp?rev=94993&r1=94992&r2=94993&view=diff
==============================================================================
--- llvm/trunk/lib/VMCore/ConstantFold.cpp (original)
+++ llvm/trunk/lib/VMCore/ConstantFold.cpp Mon Feb 1 13:35:08 2010
@@ -1506,15 +1506,16 @@
/// GlobalValues, followed by ConstantExpr's (the most complex).
///
static ICmpInst::Predicate evaluateICmpRelation(LLVMContext &Context,
- Constant *V1,
- Constant *V2,
+ Constant *V1, Constant *V2,
bool isSigned) {
assert(V1->getType() == V2->getType() &&
"Cannot compare different types of values!");
if (V1 == V2) return ICmpInst::ICMP_EQ;
- if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1)) {
- if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2)) {
+ if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1) &&
+ !isa<BlockAddress>(V1)) {
+ if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2) &&
+ !isa<BlockAddress>(V2)) {
// We distilled this down to a simple case, use the standard constant
// folder.
ConstantInt *R = 0;
@@ -1541,32 +1542,59 @@
if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
return ICmpInst::getSwappedPredicate(SwappedRelation);
- } else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(V1)) {
+ } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1)) {
if (isa<ConstantExpr>(V2)) { // Swap as necessary.
ICmpInst::Predicate SwappedRelation =
evaluateICmpRelation(Context, V2, V1, isSigned);
if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
return ICmpInst::getSwappedPredicate(SwappedRelation);
- else
- return ICmpInst::BAD_ICMP_PREDICATE;
+ return ICmpInst::BAD_ICMP_PREDICATE;
}
- // Now we know that the RHS is a GlobalValue or simple constant,
- // which (since the types must match) means that it's a ConstantPointerNull.
- if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) {
+ // Now we know that the RHS is a GlobalValue, BlockAddress or simple
+ // constant (which, since the types must match, means that it's a
+ // ConstantPointerNull).
+ if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
// Don't try to decide equality of aliases.
- if (!isa<GlobalAlias>(CPR1) && !isa<GlobalAlias>(CPR2))
- if (!CPR1->hasExternalWeakLinkage() || !CPR2->hasExternalWeakLinkage())
+ if (!isa<GlobalAlias>(GV) && !isa<GlobalAlias>(GV2))
+ if (!GV->hasExternalWeakLinkage() || !GV2->hasExternalWeakLinkage())
return ICmpInst::ICMP_NE;
+ } else if (isa<BlockAddress>(V2)) {
+ return ICmpInst::ICMP_NE; // Globals never equal labels.
} else {
assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
- // GlobalVals can never be null. Don't try to evaluate aliases.
- if (!CPR1->hasExternalWeakLinkage() && !isa<GlobalAlias>(CPR1))
+ // GlobalVals can never be null unless they have external weak linkage.
+ // We don't try to evaluate aliases here.
+ if (!GV->hasExternalWeakLinkage() && !isa<GlobalAlias>(GV))
return ICmpInst::ICMP_NE;
}
+ } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(V1)) {
+ if (isa<ConstantExpr>(V2)) { // Swap as necessary.
+ ICmpInst::Predicate SwappedRelation =
+ evaluateICmpRelation(Context, V2, V1, isSigned);
+ if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
+ return ICmpInst::getSwappedPredicate(SwappedRelation);
+ return ICmpInst::BAD_ICMP_PREDICATE;
+ }
+
+ // Now we know that the RHS is a GlobalValue, BlockAddress or simple
+ // constant (which, since the types must match, means that it is a
+ // ConstantPointerNull).
+ if (const BlockAddress *BA2 = dyn_cast<BlockAddress>(V2)) {
+ // Block address in another function can't equal this one, but block
+ // addresses in the current function might be the same if blocks are
+ // empty.
+ if (BA2->getFunction() != BA->getFunction())
+ return ICmpInst::ICMP_NE;
+ } else {
+ // Block addresses aren't null, don't equal the address of globals.
+ assert((isa<ConstantPointerNull>(V2) || isa<GlobalValue>(V2)) &&
+ "Canonicalization guarantee!");
+ return ICmpInst::ICMP_NE;
+ }
} else {
// Ok, the LHS is known to be a constantexpr. The RHS can be any of a
- // constantexpr, a CPR, or a simple constant.
+ // constantexpr, a global, block address, or a simple constant.
ConstantExpr *CE1 = cast<ConstantExpr>(V1);
Constant *CE1Op0 = CE1->getOperand(0);
@@ -1621,9 +1649,9 @@
return ICmpInst::ICMP_EQ;
}
// Otherwise, we can't really say if the first operand is null or not.
- } else if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) {
+ } else if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
if (isa<ConstantPointerNull>(CE1Op0)) {
- if (CPR2->hasExternalWeakLinkage())
+ if (GV2->hasExternalWeakLinkage())
// Weak linkage GVals could be zero or not. We're comparing it to
// a null pointer, so its less-or-equal
return isSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
@@ -1631,8 +1659,8 @@
// If its not weak linkage, the GVal must have a non-zero address
// so the result is less-than
return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
- } else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(CE1Op0)) {
- if (CPR1 == CPR2) {
+ } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
+ if (GV == GV2) {
// If this is a getelementptr of the same global, then it must be
// different. Because the types must match, the getelementptr could
// only have at most one index, and because we fold getelementptr's
Modified: llvm/trunk/test/Transforms/ConstProp/basictest.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ConstProp/basictest.ll?rev=94993&r1=94992&r2=94993&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/ConstProp/basictest.ll (original)
+++ llvm/trunk/test/Transforms/ConstProp/basictest.ll Mon Feb 1 13:35:08 2010
@@ -19,3 +19,15 @@
ret i32 %Ret
}
+
+; PR6197
+define i1 @test2(i8* %f) nounwind {
+entry:
+ %V = icmp ne i8* blockaddress(@test2, %bb), null
+ br label %bb
+bb:
+ ret i1 %V
+
+; CHECK: @test2
+; CHECK: ret i1 true
+}
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