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Clean up the usage of evaluateICmpRelation's return value.

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Add another line to the ConstantExprFold test to demonstrate the GEPs may not
wrap around in either the signed or unsigned senses.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82361 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2009-09-20 04:27:06 +00:00
parent 256db9bf9d
commit 3892baac42
2 changed files with 31 additions and 37 deletions
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67
lib/VMCore/ConstantFold.cpp
View File

@ -1263,7 +1263,7 @@ static ICmpInst::Predicate evaluateICmpRelation(LLVMContext &Context,
else
// If its not weak linkage, the GVal must have a non-zero address
// so the result is greater-than
return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
} else if (isa<ConstantPointerNull>(CE1Op0)) {
// If we are indexing from a null pointer, check to see if we have any
// non-zero indices.
@ -1567,64 +1567,57 @@ Constant *llvm::ConstantFoldCompareInstruction(LLVMContext &Context,
case ICmpInst::ICMP_EQ: // We know the constants are equal!
// If we know the constants are equal, we can decide the result of this
// computation precisely.
Result = (pred == ICmpInst::ICMP_EQ ||
pred == ICmpInst::ICMP_ULE ||
pred == ICmpInst::ICMP_SLE ||
pred == ICmpInst::ICMP_UGE ||
pred == ICmpInst::ICMP_SGE);
Result = ICmpInst::isTrueWhenEqual((ICmpInst::Predicate)pred);
break;
case ICmpInst::ICMP_ULT:
// If we know that C1 < C2, we can decide the result of this computation
// precisely.
Result = (pred == ICmpInst::ICMP_ULT ||
pred == ICmpInst::ICMP_NE ||
pred == ICmpInst::ICMP_ULE);
switch (pred) {
case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_ULE:
Result = 1; break;
case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_UGE:
Result = 0; break;
}
break;
case ICmpInst::ICMP_SLT:
// If we know that C1 < C2, we can decide the result of this computation
// precisely.
Result = (pred == ICmpInst::ICMP_SLT ||
pred == ICmpInst::ICMP_NE ||
pred == ICmpInst::ICMP_SLE);
switch (pred) {
case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SLE:
Result = 1; break;
case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SGE:
Result = 0; break;
}
break;
case ICmpInst::ICMP_UGT:
// If we know that C1 > C2, we can decide the result of this computation
// precisely.
Result = (pred == ICmpInst::ICMP_UGT ||
pred == ICmpInst::ICMP_NE ||
pred == ICmpInst::ICMP_UGE);
switch (pred) {
case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_UGE:
Result = 1; break;
case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_ULE:
Result = 0; break;
}
break;
case ICmpInst::ICMP_SGT:
// If we know that C1 > C2, we can decide the result of this computation
// precisely.
Result = (pred == ICmpInst::ICMP_SGT ||
pred == ICmpInst::ICMP_NE ||
pred == ICmpInst::ICMP_SGE);
switch (pred) {
case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SGE:
Result = 1; break;
case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SLE:
Result = 0; break;
}
break;
case ICmpInst::ICMP_ULE:
// If we know that C1 <= C2, we can only partially decide this relation.
if (pred == ICmpInst::ICMP_UGT) Result = 0;
if (pred == ICmpInst::ICMP_ULT) Result = 1;
if (pred == ICmpInst::ICMP_ULT || pred == ICmpInst::ICMP_ULE) Result = 1;
break;
case ICmpInst::ICMP_SLE:
// If we know that C1 <= C2, we can only partially decide this relation.
if (pred == ICmpInst::ICMP_SGT) Result = 0;
if (pred == ICmpInst::ICMP_SLT) Result = 1;
if (pred == ICmpInst::ICMP_SLT || pred == ICmpInst::ICMP_SLE) Result = 1;
break;
case ICmpInst::ICMP_UGE:
// If we know that C1 >= C2, we can only partially decide this relation.
if (pred == ICmpInst::ICMP_ULT) Result = 0;
if (pred == ICmpInst::ICMP_UGT) Result = 1;
if (pred == ICmpInst::ICMP_UGT || pred == ICmpInst::ICMP_UGE) Result = 1;
break;
case ICmpInst::ICMP_SGE:
// If we know that C1 >= C2, we can only partially decide this relation.
if (pred == ICmpInst::ICMP_SLT) Result = 0;
if (pred == ICmpInst::ICMP_SGT) Result = 1;
if (pred == ICmpInst::ICMP_SGT || pred == ICmpInst::ICMP_SGE) Result = 1;
break;
case ICmpInst::ICMP_NE:
// If we know that C1 != C2, we can only partially decide this relation.
if (pred == ICmpInst::ICMP_EQ) Result = 0;
if (pred == ICmpInst::ICMP_NE) Result = 1;
break;

1
test/Assembler/ConstantExprFold.ll
View File

@ -19,6 +19,7 @@ global i64* inttoptr (i64 xor (i64 ptrtoint (i64* @A to i64), i64 0) to i64*) ;
@B = external global %Ty
global i1 icmp slt (i64* @A, i64* getelementptr (i64* @A, i64 1)) ; true
global i1 icmp ult (i64* @A, i64* getelementptr (i64* @A, i64 1)) ; true
global i1 icmp slt (i64* @A, i64* getelementptr (i64* @A, i64 0)) ; false
global i1 icmp slt (i32* getelementptr (%Ty* @B, i64 0, i32 0),
i32* getelementptr (%Ty* @B, i64 0, i32 1)) ; true