[llvm] d269255 - [AArch64] Respect reserved registers while renaming in LdSt opt.

Florian Hahn via llvm-commits llvm-commits at lists.llvm.org
Sat Dec 21 06:11:07 PST 2019


Author: Florian Hahn
Date: 2019-12-21T15:10:07+01:00
New Revision: d269255b95151dcd232c8856206b7e79d70eda29

URL: https://github.com/llvm/llvm-project/commit/d269255b95151dcd232c8856206b7e79d70eda29
DIFF: https://github.com/llvm/llvm-project/commit/d269255b95151dcd232c8856206b7e79d70eda29.diff

LOG: [AArch64] Respect reserved registers while renaming in LdSt opt.

We cannot pick reserved registers as rename registers.

Fixes https://bugs.llvm.org/show_bug.cgi?id=44358

Added: 
    llvm/test/CodeGen/AArch64/stp-opt-with-renaming-reserved-regs.mir

Modified: 
    llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp b/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
index f2ff26ee0780..3156bb446963 100644
--- a/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
+++ b/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
@@ -26,6 +26,7 @@
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineOperand.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/TargetRegisterInfo.h"
 #include "llvm/IR/DebugLoc.h"
 #include "llvm/MC/MCRegisterInfo.h"
@@ -1374,6 +1375,7 @@ static Optional<MCPhysReg> tryToFindRegisterToRename(
     SmallPtrSetImpl<const TargetRegisterClass *> &RequiredClasses,
     const TargetRegisterInfo *TRI) {
   auto &MF = *FirstMI.getParent()->getParent();
+  MachineRegisterInfo &RegInfo = MF.getRegInfo();
 
   // Checks if any sub- or super-register of PR is callee saved.
   auto AnySubOrSuperRegCalleePreserved = [&MF, TRI](MCPhysReg PR) {
@@ -1397,7 +1399,8 @@ static Optional<MCPhysReg> tryToFindRegisterToRename(
   auto *RegClass = TRI->getMinimalPhysRegClass(getLdStRegOp(FirstMI).getReg());
   for (const MCPhysReg &PR : *RegClass) {
     if (DefinedInBB.available(PR) && UsedInBetween.available(PR) &&
-        !AnySubOrSuperRegCalleePreserved(PR) && CanBeUsedForAllClasses(PR)) {
+        !RegInfo.isReserved(PR) && !AnySubOrSuperRegCalleePreserved(PR) &&
+        CanBeUsedForAllClasses(PR)) {
       DefinedInBB.addReg(PR);
       LLVM_DEBUG(dbgs() << "Found rename register " << printReg(PR, TRI)
                         << "\n");

diff  --git a/llvm/test/CodeGen/AArch64/stp-opt-with-renaming-reserved-regs.mir b/llvm/test/CodeGen/AArch64/stp-opt-with-renaming-reserved-regs.mir
new file mode 100644
index 000000000000..6a8fae0f7419
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/stp-opt-with-renaming-reserved-regs.mir
@@ -0,0 +1,89 @@
+# RUN: llc -run-pass=aarch64-ldst-opt -mattr=+reserve-x10 -mattr=+reserve-x11 \
+# RUN:     -mattr=+reserve-x15 -mtriple=arm64-apple-iphoneos -verify-machineinstrs \
+# RUN:     -o - %s | FileCheck --check-prefix=CHECK --check-prefix=PRESERVED %s
+
+# RUN: llc -run-pass=aarch64-ldst-opt -mtriple=arm64-apple-iphoneos -verify-machineinstrs \
+# RUN:     -o - %s | FileCheck --check-prefix=CHECK --check-prefix=NOPRES %s
+
+
+# Make sure we do not pick reserved registers. For test1, we would pick x10,
+# and for test2 we would pick x15, both of which are reserved.
+#
+---
+# CHECK-LABEL: name: test1
+# CHECK:       bb.0:
+# CHECK-NEXT:     liveins: $x0, $x1
+# PRESERVED:      $x12, renamable $x8 = LDPXi renamable $x0, 0 :: (load 8)
+# NOPRES:         $x10, renamable $x8 = LDPXi renamable $x0, 0 :: (load 8)
+# CHECK-NEXT:     renamable $x9 = LDRXui renamable $x0, 1 :: (load 8)
+# CHECK-NEXT:     STRXui renamable $x9, renamable $x0, 100 :: (store 8, align 4)
+# CHECK-NEXT:     renamable $x8 = ADDXrr $x8, $x8
+# PRESERVED-NEXT: STPXi renamable $x8, killed $x12, renamable $x0, 10 :: (store 8, align 4)
+# NOPRES-NEXT:    STPXi renamable $x8, killed $x10, renamable $x0, 10 :: (store 8, align 4)
+# CHECK-NEXT:     RET undef $lr
+
+name:            test1
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$x1' }
+  - { reg: '$x8' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo: {}
+body:             |
+  bb.0:
+    liveins: $x0, $x1
+    renamable $x9, renamable $x8 = LDPXi renamable $x0, 0 :: (load 8)
+    STRXui renamable killed $x9, renamable $x0, 11 :: (store 8, align 4)
+    renamable $x9 = LDRXui renamable $x0, 1 :: (load 8)
+    STRXui renamable $x9, renamable $x0, 100 :: (store 8, align 4)
+    renamable $x8 = ADDXrr $x8, $x8
+    STRXui renamable $x8, renamable $x0, 10 :: (store 8, align 4)
+    RET undef $lr
+
+...
+# CHECK-LABEL: name: test2
+# CHECK:       bb.0:
+# CHECK-NEXT:     liveins: $x0, $x1, $x10, $x11, $x12, $x13
+# CHECK:          renamable $w19 = LDRWui renamable $x0, 0 :: (load 8)
+# PRESERVED-NEXT: $x18, renamable $x8 = LDPXi renamable $x0, 1 :: (load 8)
+# NOPRES-NEXT:    $x15, renamable $x8 = LDPXi renamable $x0, 1 :: (load 8)
+# CHECK-NEXT:     renamable $x9 = LDRXui renamable $x0, 3 :: (load 8)
+# CHECK-NEXT:     renamable $x14 = LDRXui renamable $x0, 5 :: (load 8)
+# PRESERVED-NEXT: STPXi renamable $x9, killed $x18, renamable $x0, 10 :: (store 8, align 4)
+# NOPRES-NEXT:    STPXi renamable $x9, killed $x15, renamable $x0, 10 :: (store 8, align 4)
+# CHECK-NEXT:     STRXui killed renamable $x14, renamable $x0, 200 :: (store 8, align 4)
+# CHECK-NEXT:     renamable $w8 = ADDWrr $w19, $w19
+# CHECK-NEXT:     STRWui renamable $w8, renamable $x0, 100 :: (store 8, align 4)
+# CHECK-NEXT:     RET undef $lr
+#
+name:            test2
+alignment:       4
+tracksRegLiveness: true
+liveins:
+  - { reg: '$x0' }
+  - { reg: '$x1' }
+  - { reg: '$x8' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo: {}
+body:             |
+  bb.0:
+    liveins: $x0, $x1, $x10, $x11, $x12, $x13
+    renamable $w19 = LDRWui renamable $x0, 0 :: (load 8)
+    renamable $x9, renamable $x8 = LDPXi renamable $x0, 1 :: (load 8)
+    STRXui renamable killed $x9, renamable $x0, 11 :: (store 8, align 4)
+    renamable $x9 = LDRXui renamable $x0, 3 :: (load 8)
+    renamable $x14 = LDRXui renamable $x0, 5 :: (load 8)
+    STRXui renamable $x9, renamable $x0, 10 :: (store 8, align 4)
+    STRXui renamable killed $x14, renamable $x0, 200 :: (store 8, align 4)
+    renamable $w8 = ADDWrr $w19, $w19
+    STRWui renamable $w8, renamable $x0, 100 :: (store 8, align 4)
+    RET undef $lr
+
+...
+---


        


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