[PATCH] D140672: [TwoAddressInstruction] Contrain RegClass when processing a statepoint

[Danila Malyutin via Phabricator via llvm-commits]

danilaml created this revision.
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This transformation could've triggered a verifier assert if RegA and RegB
were of different reg classes. Fix this by constraining as the comment
for replaceRegWith suggests.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D140672

Files:
  llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
  llvm/test/CodeGen/AArch64/statepoint-twoaddr.mir


Index: llvm/test/CodeGen/AArch64/statepoint-twoaddr.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/statepoint-twoaddr.mir
@@ -0,0 +1,41 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=aarch64-unknown-linux -run-pass=twoaddressinstruction -verify-machineinstrs %s -o - | FileCheck %s
+# REQUIRES: aarch64-registered-target
+
+# Verify that the register class is correctly constrained after the twoaddress replacement
+---
+name:              statepoint_twoaddr
+tracksRegLiveness: true
+stack:
+  - { id: 0, name: '', type: default, offset: 0, size: 4, alignment: 4,
+      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -4, debug-info-variable: '', debug-info-expression: '',
+      debug-info-location: '' }
+body:              |
+  bb.0:
+    liveins: $w0
+
+    ; CHECK-LABEL: name: statepoint_twoaddr
+    ; CHECK: liveins: $w0
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr64sp = COPY killed $x0
+    ; CHECK-NEXT: [[MOVi32imm:%[0-9]+]]:gpr32 = MOVi32imm 8
+    ; CHECK-NEXT: [[SUBREG_TO_REG:%[0-9]+]]:gpr64all = SUBREG_TO_REG 0, killed [[MOVi32imm]], %subreg.sub_32
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:gpr64all = COPY $xzr
+    ; CHECK-NEXT: $x1 = COPY [[SUBREG_TO_REG]]
+    ; CHECK-NEXT: $x2 = COPY killed [[SUBREG_TO_REG]]
+    ; CHECK-NEXT: [[STATEPOINT:%[0-9]+]]:gpr64sp = STATEPOINT 2882400000, 0, 4, killed [[COPY1]], undef $x0, killed $x1, killed $x2, undef $x3, 2, 125, 2, 4, 2, 47, 2, 0, 2, 2, 2, 0, 2, 17, 2, 1, 2, 13, 2, 0, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 3, 1, 4, %stack.0, 0, 2, 0, 2, 4278124286, 2, 4, 2, 4278124286, 2, 7, 2, 0, 2, 4, 2, 0, 2, 7, 2, 0, 2, 1, 2, 2, 2, 19, 2, 0, 2, 3, 2, 0, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 3, 2, 4278124286, 2, 2, killed [[STATEPOINT]](tied-def 0), 2, 4278124286, 2, 0, 2, 2, 0, 0, 1, 1, csr_aarch64_aapcs, implicit-def $sp, implicit-def dead $x0, implicit-def dead early-clobber $lr :: (volatile load store (s32) on %stack.0)
+    ; CHECK-NEXT: [[ADDXri:%[0-9]+]]:gpr64sp = ADDXri killed [[STATEPOINT]], 16, 0
+    ; CHECK-NEXT: $x0 = COPY killed [[ADDXri]]
+    ; CHECK-NEXT: RET_ReallyLR implicit $x0
+    %0:gpr64all = COPY killed $x0
+    %1:gpr32 = MOVi32imm 8
+    %2:gpr64all = SUBREG_TO_REG 0, killed %1, %subreg.sub_32
+    %3:gpr64all = COPY $xzr
+    $x1 = COPY %2
+    $x2 = COPY killed %2
+    %4:gpr64sp = STATEPOINT 2882400000, 0, 4, killed %3, undef $x0, killed $x1, killed $x2, undef $x3, 2, 125, 2, 4, 2, 47, 2, 0, 2, 2, 2, 0, 2, 17, 2, 1, 2, 13, 2, 0, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 3, 1, 4, %stack.0, 0, 2, 0, 2, 4278124286, 2, 4, 2, 4278124286, 2, 7, 2, 0, 2, 4, 2, 0, 2, 7, 2, 0, 2, 1, 2, 2, 2, 19, 2, 0, 2, 3, 2, 0, 2, 0, 2, 4278124286, 2, 0, 2, 4278124286, 2, 3, 2, 4278124286, 2, 2, killed %0(tied-def 0), 2, 4278124286, 2, 0, 2, 2, 0, 0, 1, 1, csr_aarch64_aapcs, implicit-def $sp, implicit-def dead $x0, implicit-def dead early-clobber $lr :: (volatile load store (s32) on %stack.0)
+    %5:gpr64sp = ADDXri killed %4, 16, 0
+    $x0 = COPY killed %5
+    RET_ReallyLR implicit $x0
+...
Index: llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
===================================================================
--- llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -1681,6 +1681,13 @@
       continue;
     }
 
+    if (!MRI->constrainRegClass(RegB, MRI->getRegClass(RegA))) {
+      LLVM_DEBUG(dbgs() << "MRI: couldn't constrain" << printReg(RegB, TRI, 0)
+                        << " to register class of " << printReg(RegA, TRI, 0)
+                        << '\n');
+      NeedCopy = true;
+      continue;
+    }
     MRI->replaceRegWith(RegA, RegB);
 
     if (LIS) {


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