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-rw-r--r--llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp8
-rw-r--r--llvm/test/CodeGen/AArch64/ldst-opt.mir19
2 files changed, 26 insertions, 1 deletions
diff --git a/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp b/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
index c45c0b4c8ed..005f2d51e40 100644
--- a/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
+++ b/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
@@ -808,7 +808,13 @@ AArch64LoadStoreOpt::promoteLoadFromStore(MachineBasicBlock::iterator LoadI,
// Remove the load, if the destination register of the loads is the same
// register for stored value.
if (StRt == LdRt && LoadSize == 8) {
- StoreI->clearRegisterKills(StRt, TRI);
+ for (MachineInstr &MI : make_range(StoreI->getIterator(),
+ LoadI->getIterator())) {
+ if (MI.killsRegister(StRt, TRI)) {
+ MI.clearRegisterKills(StRt, TRI);
+ break;
+ }
+ }
DEBUG(dbgs() << "Remove load instruction:\n ");
DEBUG(LoadI->print(dbgs()));
DEBUG(dbgs() << "\n");
diff --git a/llvm/test/CodeGen/AArch64/ldst-opt.mir b/llvm/test/CodeGen/AArch64/ldst-opt.mir
index 5b3576d898e..9cb9528cc62 100644
--- a/llvm/test/CodeGen/AArch64/ldst-opt.mir
+++ b/llvm/test/CodeGen/AArch64/ldst-opt.mir
@@ -162,3 +162,22 @@ body: |
# CHECK: UBFMWri undef %w1
# CHECK: STRHHui undef %w3
# CHECK: ANDWri undef %w3
+---
+name: promote-load-from-store-trivial-kills
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: %x0, %lr
+
+ STRXui %x0, %sp, 0 :: (store 8)
+ STRXui killed %x0, %sp, 2 :: (store 8)
+ %x0 = LDRXui %sp, 0 :: (load 8)
+ BL $bar, csr_aarch64_aapcs, implicit-def %lr, implicit %sp, implicit %x0, implicit-def %sp
+ RET %lr
+...
+# CHECK-LABEL: name: promote-load-from-store-trivial-kills
+# CHECK: STRXui %x0, %sp, 0
+# CHECK: STRXui %x0, %sp, 2
+# CHECK-NOT: LDRXui
+# CHECK-NOT: ORR
+# CHECK: BL $bar, csr_aarch64_aapcs, implicit-def %lr, implicit %sp, implicit %x0, implicit-def %sp
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