[llvm] a68d72a - MachineVerifier: Don't crash in LiveIntervals checks on generic vregs

[Matt Arsenault via llvm-commits]

Author: Matt Arsenault
Date: 2023-09-01T08:32:02-04:00
New Revision: a68d72a9950f01b7ed7e8be98eabab5f69d254be

URL: https://github.com/llvm/llvm-project/commit/a68d72a9950f01b7ed7e8be98eabab5f69d254be
DIFF: https://github.com/llvm/llvm-project/commit/a68d72a9950f01b7ed7e8be98eabab5f69d254be.diff

LOG: MachineVerifier: Don't crash in LiveIntervals checks on generic vregs

If llvm-reduce is going to unconditionally verify functions with
LiveIntervals, it needs to be tolerant of generic vregs.

https://reviews.llvm.org/D133813

Added: 
    

Modified: 
    llvm/include/llvm/CodeGen/MachineRegisterInfo.h
    llvm/lib/CodeGen/MachineVerifier.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/CodeGen/MachineRegisterInfo.h b/llvm/include/llvm/CodeGen/MachineRegisterInfo.h
index 496224a85c52c3..9bca74a1d4fc82 100644
--- a/llvm/include/llvm/CodeGen/MachineRegisterInfo.h
+++ b/llvm/include/llvm/CodeGen/MachineRegisterInfo.h
@@ -229,7 +229,8 @@ class MachineRegisterInfo {
   }
   bool shouldTrackSubRegLiveness(Register VReg) const {
     assert(VReg.isVirtual() && "Must pass a VReg");
-    return shouldTrackSubRegLiveness(*getRegClass(VReg));
+    const TargetRegisterClass *RC = getRegClassOrNull(VReg);
+    return LLVM_LIKELY(RC) ? shouldTrackSubRegLiveness(*RC) : false;
   }
   bool subRegLivenessEnabled() const {
     return TracksSubRegLiveness;

diff  --git a/llvm/lib/CodeGen/MachineVerifier.cpp b/llvm/lib/CodeGen/MachineVerifier.cpp
index c626b41feafac1..cfca2d4ba6798f 100644
--- a/llvm/lib/CodeGen/MachineVerifier.cpp
+++ b/llvm/lib/CodeGen/MachineVerifier.cpp
@@ -3383,26 +3383,28 @@ void MachineVerifier::verifyLiveInterval(const LiveInterval &LI) {
   assert(Reg.isVirtual());
   verifyLiveRange(LI, Reg);
 
-  LaneBitmask Mask;
-  LaneBitmask MaxMask = MRI->getMaxLaneMaskForVReg(Reg);
-  for (const LiveInterval::SubRange &SR : LI.subranges()) {
-    if ((Mask & SR.LaneMask).any()) {
-      report("Lane masks of sub ranges overlap in live interval", MF);
-      report_context(LI);
-    }
-    if ((SR.LaneMask & ~MaxMask).any()) {
-      report("Subrange lanemask is invalid", MF);
-      report_context(LI);
-    }
-    if (SR.empty()) {
-      report("Subrange must not be empty", MF);
-      report_context(SR, LI.reg(), SR.LaneMask);
-    }
-    Mask |= SR.LaneMask;
-    verifyLiveRange(SR, LI.reg(), SR.LaneMask);
-    if (!LI.covers(SR)) {
-      report("A Subrange is not covered by the main range", MF);
-      report_context(LI);
+  if (LI.hasSubRanges()) {
+    LaneBitmask Mask;
+    LaneBitmask MaxMask = MRI->getMaxLaneMaskForVReg(Reg);
+    for (const LiveInterval::SubRange &SR : LI.subranges()) {
+      if ((Mask & SR.LaneMask).any()) {
+        report("Lane masks of sub ranges overlap in live interval", MF);
+        report_context(LI);
+      }
+      if ((SR.LaneMask & ~MaxMask).any()) {
+        report("Subrange lanemask is invalid", MF);
+        report_context(LI);
+      }
+      if (SR.empty()) {
+        report("Subrange must not be empty", MF);
+        report_context(SR, LI.reg(), SR.LaneMask);
+      }
+      Mask |= SR.LaneMask;
+      verifyLiveRange(SR, LI.reg(), SR.LaneMask);
+      if (!LI.covers(SR)) {
+        report("A Subrange is not covered by the main range", MF);
+        report_context(LI);
+      }
     }
   }