"Surprising getelementptr!");
return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
} else {
- // If they are different globals, we don't know what the value is,
- // but they can't be equal.
- return ICmpInst::ICMP_NE;
+ // If they are different globals, we don't know what the value is.
+ return ICmpInst::BAD_ICMP_PREDICATE;
}
}
} else {
default: break;
case Instruction::GetElementPtr:
// By far the most common case to handle is when the base pointers are
- // obviously to the same or different globals.
+ // obviously to the same global.
if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
- if (CE1Op0 != CE2Op0) // Don't know relative ordering, but not equal
- return ICmpInst::ICMP_NE;
+ if (CE1Op0 != CE2Op0) // Don't know relative ordering.
+ return ICmpInst::BAD_ICMP_PREDICATE;
// Ok, we know that both getelementptr instructions are based on the
// same global. From this, we can precisely determine the relative
// ordering of the resultant pointers.
--- /dev/null
+; This test checks to make sure that constant exprs don't fold in some simple
+; situations
+
+; RUN: llvm-as < %s | llvm-dis | FileCheck %s
+
+; Even give it a datalayout, to tempt folding as much as possible.
+target datalayout = "p:32:32"
+
+@A = global i64 0
+@B = global i64 0
+
+; Don't fold this. @A might really be allocated next to @B, in which case the
+; icmp should return true. It's not valid to *dereference* in @B from a pointer
+; based on @A, but icmp isn't a dereference.
+
+; CHECK: @C = global i1 icmp eq (i64* getelementptr inbounds (i64* @A, i64 1), i64* @B)
+@C = global i1 icmp eq (i64* getelementptr inbounds (i64* @A, i64 1), i64* @B)
+
+; Don't fold this completely away either. In theory this could be simplified
+; to only use a gep on one side of the icmp though.
+
+; CHECK: @D = global i1 icmp eq (i64* getelementptr inbounds (i64* @A, i64 1), i64* getelementptr inbounds (i64* @B, i64 2))
+@D = global i1 icmp eq (i64* getelementptr inbounds (i64* @A, i64 1), i64* getelementptr inbounds (i64* @B, i64 2))