[llvm] 6e52eeb - [MemCpyOpt] Add test for incorrect optimization across lifetime (NFC)

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2021-01-29T12:57:02+01:00
New Revision: 6e52eebc2a68f34aa19a2b80f1b763aac692d542

URL: https://github.com/llvm/llvm-project/commit/6e52eebc2a68f34aa19a2b80f1b763aac692d542
DIFF: https://github.com/llvm/llvm-project/commit/6e52eebc2a68f34aa19a2b80f1b763aac692d542.diff

LOG: [MemCpyOpt] Add test for incorrect optimization across lifetime (NFC)

This only affects the MemorySSA-based implementation.

Added: 
    

Modified: 
    llvm/test/Transforms/MemCpyOpt/lifetime.ll

Removed: 
    


################################################################################
diff  --git a/llvm/test/Transforms/MemCpyOpt/lifetime.ll b/llvm/test/Transforms/MemCpyOpt/lifetime.ll
index 1d2b699ee96d..5dc13ca10054 100644
--- a/llvm/test/Transforms/MemCpyOpt/lifetime.ll
+++ b/llvm/test/Transforms/MemCpyOpt/lifetime.ll
@@ -1,6 +1,6 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -O2 -S -enable-memcpyopt-memoryssa=0 | FileCheck %s
-; RUN: opt < %s -O2 -S -enable-memcpyopt-memoryssa=1 -verify-memoryssa | FileCheck %s
+; RUN: opt < %s -O2 -S -enable-memcpyopt-memoryssa=0 | FileCheck %s --check-prefixes=CHECK,NO_MSSA
+; RUN: opt < %s -O2 -S -enable-memcpyopt-memoryssa=1 -verify-memoryssa | FileCheck %s --check-prefixes=CHECK,MSSA
 
 ; performCallSlotOptzn in MemCpy should not exchange the calls to
 ; @llvm.lifetime.start and @llvm.memcpy.
@@ -9,8 +9,8 @@ declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i
 declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #1
 declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #1
 
-define void @_ZN4CordC2EOS_(i8* nocapture dereferenceable(16) %arg1) {
-; CHECK-LABEL: @_ZN4CordC2EOS_(
+define void @call_slot(i8* nocapture dereferenceable(16) %arg1) {
+; CHECK-LABEL: @call_slot(
 ; CHECK-NEXT:  bb:
 ; CHECK-NEXT:    [[TMP_SROA_3_0_ARG1_SROA_RAW_IDX:%.*]] = getelementptr inbounds i8, i8* [[ARG1:%.*]], i64 7
 ; CHECK-NEXT:    store i8 0, i8* [[TMP_SROA_3_0_ARG1_SROA_RAW_IDX]], align 1
@@ -27,4 +27,39 @@ bb:
   ret void
 }
 
+; FIXME: Miscompile.
+define void @memcpy_memcpy_across_lifetime(i8* noalias %p1, i8* noalias %p2, i8* noalias %p3) {
+; NO_MSSA-LABEL: @memcpy_memcpy_across_lifetime(
+; NO_MSSA-NEXT:    [[A:%.*]] = alloca [16 x i8], align 1
+; NO_MSSA-NEXT:    [[A8:%.*]] = getelementptr inbounds [16 x i8], [16 x i8]* [[A]], i64 0, i64 0
+; NO_MSSA-NEXT:    call void @llvm.lifetime.start.p0i8(i64 16, i8* nonnull [[A8]])
+; NO_MSSA-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 dereferenceable(16) [[A8]], i8* nonnull align 1 dereferenceable(16) [[P1:%.*]], i64 16, i1 false)
+; NO_MSSA-NEXT:    tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 dereferenceable(16) [[P1]], i8* nonnull align 1 dereferenceable(16) [[P2:%.*]], i64 16, i1 false)
+; NO_MSSA-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 dereferenceable(16) [[P2]], i8* nonnull align 1 dereferenceable(16) [[A8]], i64 16, i1 false)
+; NO_MSSA-NEXT:    call void @llvm.lifetime.end.p0i8(i64 16, i8* nonnull [[A8]])
+; NO_MSSA-NEXT:    tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 dereferenceable(16) [[P3:%.*]], i8* nonnull align 1 dereferenceable(16) [[P2]], i64 16, i1 false)
+; NO_MSSA-NEXT:    ret void
+;
+; MSSA-LABEL: @memcpy_memcpy_across_lifetime(
+; MSSA-NEXT:    [[A:%.*]] = alloca [16 x i8], align 1
+; MSSA-NEXT:    [[A8:%.*]] = getelementptr inbounds [16 x i8], [16 x i8]* [[A]], i64 0, i64 0
+; MSSA-NEXT:    call void @llvm.lifetime.start.p0i8(i64 16, i8* nonnull [[A8]])
+; MSSA-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 dereferenceable(16) [[A8]], i8* nonnull align 1 dereferenceable(16) [[P1:%.*]], i64 16, i1 false)
+; MSSA-NEXT:    tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 dereferenceable(16) [[P1]], i8* nonnull align 1 dereferenceable(16) [[P2:%.*]], i64 16, i1 false)
+; MSSA-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 dereferenceable(16) [[P2]], i8* nonnull align 1 dereferenceable(16) [[A8]], i64 16, i1 false)
+; MSSA-NEXT:    call void @llvm.lifetime.end.p0i8(i64 16, i8* nonnull [[A8]])
+; MSSA-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 dereferenceable(16) [[P3:%.*]], i8* nonnull align 1 dereferenceable(16) [[A8]], i64 16, i1 false)
+; MSSA-NEXT:    ret void
+;
+  %a = alloca [16 x i8]
+  %a8 = bitcast [16 x i8]* %a to i8*
+  call void @llvm.lifetime.start.p0i8(i64 16, i8* %a8)
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %a8, i8* %p1, i64 16, i1 false)
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %p1, i8* %p2, i64 16, i1 false)
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %p2, i8* %a8, i64 16, i1 false)
+  call void @llvm.lifetime.end.p0i8(i64 16, i8* %a8)
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %p3, i8* %p2, i64 16, i1 false)
+  ret void
+}
+
 attributes #1 = { argmemonly nounwind }