if (!Repl || firstInBB(I, Repl))
Repl = I;
+ // Keep track of whether we moved the instruction so we know whether we
+ // should move the MemoryAccess.
+ bool MoveAccess = true;
if (Repl) {
// Repl is already in HoistPt: it remains in place.
assert(allOperandsAvailable(Repl, HoistPt) &&
"instruction depends on operands that are not available");
+ MoveAccess = false;
} else {
// When we do not find Repl in HoistPt, select the first in the list
// and move it to HoistPt.
DFSNumber[Repl] = DFSNumber[Last]++;
}
- MemoryAccess *NewMemAcc = nullptr;
- if (MemoryAccess *MA = MSSA->getMemoryAccess(Repl)) {
- if (MemoryUseOrDef *OldMemAcc = dyn_cast<MemoryUseOrDef>(MA)) {
+ MemoryAccess *NewMemAcc = MSSA->getMemoryAccess(Repl);
+
+ if (MoveAccess) {
+ if (MemoryUseOrDef *OldMemAcc =
+ dyn_cast_or_null<MemoryUseOrDef>(NewMemAcc)) {
// The definition of this ld/st will not change: ld/st hoisting is
// legal when the ld/st is not moved past its current definition.
MemoryAccess *Def = OldMemAcc->getDefiningAccess();
- NewMemAcc = MSSA->createMemoryAccessInBB(Repl, Def, HoistPt,
- MemorySSA::End);
+ NewMemAcc =
+ MSSA->createMemoryAccessInBB(Repl, Def, HoistPt, MemorySSA::End);
OldMemAcc->replaceAllUsesWith(NewMemAcc);
MSSA->removeMemoryAccess(OldMemAcc);
}
--- /dev/null
+; RUN: opt -S -gvn-hoist -verify-memoryssa < %s | FileCheck %s
+
+; Check that we end up with one load and one store, in the right order
+; CHECK-LABEL: define void @test_it(
+; CHECK: store
+; CHECK-NEXT: load
+; CHECK-NOT: store
+; CHECK-NOT: load
+
+%rec894.0.1.2.3.12 = type { i16 }
+
+@a = external global %rec894.0.1.2.3.12
+
+define void @test_it() {
+bb2:
+ store i16 undef, i16* getelementptr inbounds (%rec894.0.1.2.3.12, %rec894.0.1.2.3.12* @a, i16 0, i32 0), align 1
+ %_tmp61 = load i16, i16* getelementptr inbounds (%rec894.0.1.2.3.12, %rec894.0.1.2.3.12* @a, i16 0, i32 0), align 1
+ store i16 undef, i16* getelementptr inbounds (%rec894.0.1.2.3.12, %rec894.0.1.2.3.12* @a, i16 0, i32 0), align 1
+ %_tmp92 = load i16, i16* getelementptr inbounds (%rec894.0.1.2.3.12, %rec894.0.1.2.3.12* @a, i16 0, i32 0), align 1
+ ret void
+}