[PATCH] D99287: [GlobalISel] Fix crash in RBS with a non-generic IMPLICIT_DEF.

[Amara Emerson via Phabricator via llvm-commits]

aemerson created this revision.
aemerson added reviewers: paquette, arsenm.
aemerson added a project: LLVM.
Herald added subscribers: hiraditya, rovka.
aemerson requested review of this revision.
Herald added a subscriber: wdng.

This may occur when swifterror codegen in the translator generates these, but we shouldn't try to handle them since they should have regclasses anyway.

rdar://75784009


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D99287

Files:
  llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp
  llvm/test/CodeGen/AArch64/GlobalISel/implicit_def_rbs_crash.mir


Index: llvm/test/CodeGen/AArch64/GlobalISel/implicit_def_rbs_crash.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/GlobalISel/implicit_def_rbs_crash.mir
@@ -0,0 +1,22 @@
+# RUN: llc -O0 -mtriple arm64-- -run-pass=regbankselect -verify-machineinstrs %s -o - | FileCheck %s
+
+# Check we don't crash given an non-generic implicit_def. These may
+# come from swifterror handling in the translator.
+# CHECK: IMPLICIT_DEF
+---
+name:            implicit_def_crash
+alignment:       4
+legalized:       true
+regBankSelected: false
+selected:        false
+failedISel:      false
+registers:
+  - { id: 0, class: gpr64all, preferred-register: '' }
+  - { id: 1, class: _, preferred-register: '' }
+  - { id: 2, class: gpr64all, preferred-register: '' }
+  - { id: 3, class: gpr64all, preferred-register: '' }
+body:             |
+  bb.1:
+    %0:gpr64all = IMPLICIT_DEF
+
+...
Index: llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp
===================================================================
--- llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp
+++ llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp
@@ -719,6 +719,10 @@
       if (MI.isDebugInstr())
         continue;
 
+      // Ignore IMPLICIT_DEF which must have a regclass.
+      if (MI.isImplicitDef())
+        continue;
+
       if (!assignInstr(MI)) {
         reportGISelFailure(MF, *TPC, *MORE, "gisel-regbankselect",
                            "unable to map instruction", MI);


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