[mte] fix compiler crash with musttail.

[fmayer]

Summary

see D118852 for matching hwasan fix.

[fmayer]

simplify test

[fmayer]

remove comments

[fmayer]

rebase

[eugenis]

LGTM

llvm/test/CodeGen/AArch64/stack-tagging-musttail.ll

21

It would be nice to check that settag goes before the musttail call. Also at least a brief comment about what is being tested for future maintainers ("regression test for a compiler crash ...")

[fmayer]

improve test

llvm/lib/Target/AArch64/AArch64StackTagging.cpp

for (Instruction &I : BB) {
           continue;
         }
         if (II->getIntrinsicID() == Intrinsic::lifetime_start)
           Allocas[AI].LifetimeStart.push_back(II);
         else
           Allocas[AI].LifetimeEnd.push_back(II);
       }
 
-      if (isa<ReturnInst, ResumeInst, CleanupReturnInst>(&I))
-        RetVec.push_back(&I);
+      Instruction *ExitUntag = getUntagLocationIfFunctionExit(I);
+      if (ExitUntag)
+        RetVec.push_back(ExitUntag);
     }
   }
 
   if (Allocas.empty())
     return false;
 
   int NextTag = 0;
   int NumInterestingAllocas = 0;

llvm/test/CodeGen/AArch64/stack-tagging-musttail.ll

+; RUN: opt -S -aarch64-stack-tagging -stack-tagging-use-stack-safety=0 %s -o -
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-arm-unknown-eabi"
+
+define dso_local noundef i32 @_Z3bari(i32 noundef %0) sanitize_memtag {
+  %2 = alloca i32, align 4
+  store i32 %0, i32* %2, align 4
+  %3 = load i32, i32* %2, align 4
+  ret i32 %3
+}
+
+define dso_local noundef i32 @_Z3fooi(i32 noundef %0) sanitize_memtag {
+  %2 = alloca i32, align 4
+  %3 = alloca i32, align 4
+  store i32 %0, i32* %2, align 4
+  store volatile i32 5, i32* %3, align 4
+  %4 = load i32, i32* %2, align 4
+  %5 = load volatile i32, i32* %3, align 4
+  %6 = add nsw i32 %4, %5
+  %7 = musttail call noundef i32 @_Z3bari(i32 noundef %6)
+  ret i32 %7
+}