[PATCH] D126661: [MachineVerifier] Fix crash on early clobbered subreg operands.

[Daniil Fukalov via Phabricator via llvm-commits]

This revision was not accepted when it landed; it landed in state "Needs Review".
This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG99d364d1f430: [MachineVerifier] Fix crash on early clobbered subreg operands. (authored by dfukalov).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D126661/new/

https://reviews.llvm.org/D126661

Files:
  llvm/lib/CodeGen/MachineVerifier.cpp
  llvm/test/MachineVerifier/verifier-ec-subreg-liveness.mir


Index: llvm/test/MachineVerifier/verifier-ec-subreg-liveness.mir
===================================================================
--- /dev/null
+++ llvm/test/MachineVerifier/verifier-ec-subreg-liveness.mir
@@ -0,0 +1,31 @@
+# RUN: llc -mtriple amdgcn-amd-amdhsa -run-pass=liveintervals,pipeliner -verify-machineinstrs -o - %s | FileCheck %s
+# REQUIRES: amdgpu-registered-target
+
+# This test checks that the verifier doesn't crash on early clobbered subreg arguments.
+
+---
+name:            sub0
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $vgpr0_vgpr1
+
+    ; CHECK-NOT: *** Bad machine code: Inconsistent valno->def ***
+    INLINEASM &"", 0 /* attdialect */,  1835019 /* regdef-ec:VGPR_32 */, def undef early-clobber %0.sub0:vreg_64, 1835018 /* regdef:VGPR_32 */, def undef %0.sub1:vreg_64
+    FLAT_STORE_DWORDX2 $vgpr0_vgpr1, %0, 0, 0, implicit $exec, implicit $flat_scr :: (store (s64))
+    S_ENDPGM 0
+
+...
+---
+name:            sub1
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $vgpr0_vgpr1
+
+    ; CHECK-NOT: *** Bad machine code: Inconsistent valno->def ***
+    INLINEASM &"", 0 /* attdialect */, 1835018 /* regdef:VGPR_32 */, def undef %0.sub0:vreg_64, 1835019 /* regdef-ec:VGPR_32 */, def undef early-clobber %0.sub1:vreg_64
+    FLAT_STORE_DWORDX2 $vgpr0_vgpr1, %0, 0, 0, implicit $exec, implicit $flat_scr :: (store (s64))
+    S_ENDPGM 0
+
+...
Index: llvm/lib/CodeGen/MachineVerifier.cpp
===================================================================
--- llvm/lib/CodeGen/MachineVerifier.cpp
+++ llvm/lib/CodeGen/MachineVerifier.cpp
@@ -2290,8 +2290,18 @@
                                          bool SubRangeCheck,
                                          LaneBitmask LaneMask) {
   if (const VNInfo *VNI = LR.getVNInfoAt(DefIdx)) {
-    assert(VNI && "NULL valno is not allowed");
-    if (VNI->def != DefIdx) {
+    // The LR can correspond to the whole reg and its def slot is not obliged
+    // to be the same as the MO' def slot. E.g. when we check here "normal"
+    // subreg MO but there is other EC subreg MO in the same instruction so the
+    // whole reg has EC def slot and differs from the currently checked MO' def
+    // slot. For example:
+    // %0 [16e,32r:0) 0 at 16e  L..3 [16e,32r:0) 0 at 16e  L..C [16r,32r:0) 0 at 16r
+    // Check that there is an early-clobber def of the same superregister
+    // somewhere is performed in visitMachineFunctionAfter()
+    if (((SubRangeCheck || MO->getSubReg() == 0) && VNI->def != DefIdx) ||
+        !SlotIndex::isSameInstr(VNI->def, DefIdx) ||
+        (VNI->def != DefIdx &&
+         (!VNI->def.isEarlyClobber() || !DefIdx.isRegister()))) {
       report("Inconsistent valno->def", MO, MONum);
       report_context_liverange(LR);
       report_context_vreg_regunit(VRegOrUnit);


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