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merged 2 commits into from
Nov 20, 2024
Merged

[Local] Only intersect tbaa metadata if instr moves. #116682

merged 2 commits into from
Nov 20, 2024

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fhahn
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@fhahn fhahn commented Nov 18, 2024

Preserve tbaa metadata on the replacement instruction, if it does not move. In that case, the program would be UB, if the aliasing property encoded in the metadata does not hold.

This makes use of the clarification re tbaa metadata implying UB if the property does not hold: #116220

Same as #115868, but for !tbaa

@fhahn fhahn marked this pull request as ready for review November 18, 2024 19:06
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llvmbot commented Nov 18, 2024

@llvm/pr-subscribers-llvm-transforms

Author: Florian Hahn (fhahn)

Changes

Preserve tbaa metadata on the replacement instruction, if it does not move. In that case, the program would be UB, if the aliasing property encoded in the metadata does not hold.

This makes use of the clarification re tbaa metadata implying UB if the property does not hold: #116220

Same as #115868, but for !tbaa

Full diff: https://github.com/llvm/llvm-project/pull/116682.diff

4 Files Affected:

  • (modified) llvm/lib/Transforms/Utils/Local.cpp (+2-1)
  • (modified) llvm/test/Transforms/GVN/tbaa.ll (+75-41)
  • (modified) llvm/test/Transforms/JumpThreading/thread-loads.ll (+14-8)
  • (modified) llvm/test/Transforms/NewGVN/tbaa.ll (+13-10)
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 509b6d62265517..18f0f1df50fedf 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -3326,7 +3326,8 @@ void llvm::combineMetadata(Instruction *K, const Instruction *J,
         K->mergeDIAssignID(J);
         break;
       case LLVMContext::MD_tbaa:
-        K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD));
+        if (DoesKMove)
+          K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD));
         break;
       case LLVMContext::MD_alias_scope:
         K->setMetadata(Kind, MDNode::getMostGenericAliasScope(JMD, KMD));
diff --git a/llvm/test/Transforms/GVN/tbaa.ll b/llvm/test/Transforms/GVN/tbaa.ll
index 46d1bb737a6934..b5dd3867bdbc28 100644
--- a/llvm/test/Transforms/GVN/tbaa.ll
+++ b/llvm/test/Transforms/GVN/tbaa.ll
@@ -1,10 +1,13 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
 ; RUN: opt -passes=gvn -S < %s | FileCheck %s
 
 define i32 @test1(ptr %p, ptr %q) {
-; CHECK-LABEL: @test1(ptr %p, ptr %q)
-; CHECK: call i32 @foo(ptr %p)
-; CHECK-NOT: tbaa
-; CHECK: %c = add i32 %a, %a
+; CHECK-LABEL: define i32 @test1(
+; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA0:![0-9]+]]
+; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
+; CHECK-NEXT:    ret i32 [[C]]
+;
   %a = call i32 @foo(ptr %p), !tbaa !0
   %b = call i32 @foo(ptr %p)
   %c = add i32 %a, %b
@@ -12,9 +15,12 @@ define i32 @test1(ptr %p, ptr %q) {
 }
 
 define i32 @test2(ptr %p, ptr %q) {
-; CHECK-LABEL: @test2(ptr %p, ptr %q)
-; CHECK: call i32 @foo(ptr %p), !tbaa [[TAGC:!.*]]
-; CHECK: %c = add i32 %a, %a
+; CHECK-LABEL: define i32 @test2(
+; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA0]]
+; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
+; CHECK-NEXT:    ret i32 [[C]]
+;
   %a = call i32 @foo(ptr %p), !tbaa !0
   %b = call i32 @foo(ptr %p), !tbaa !0
   %c = add i32 %a, %b
@@ -22,9 +28,12 @@ define i32 @test2(ptr %p, ptr %q) {
 }
 
 define i32 @test3(ptr %p, ptr %q) {
-; CHECK-LABEL: @test3(ptr %p, ptr %q)
-; CHECK: call i32 @foo(ptr %p), !tbaa [[TAGB:!.*]]
-; CHECK: %c = add i32 %a, %a
+; CHECK-LABEL: define i32 @test3(
+; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA4:![0-9]+]]
+; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
+; CHECK-NEXT:    ret i32 [[C]]
+;
   %a = call i32 @foo(ptr %p), !tbaa !3
   %b = call i32 @foo(ptr %p), !tbaa !3
   %c = add i32 %a, %b
@@ -32,9 +41,12 @@ define i32 @test3(ptr %p, ptr %q) {
 }
 
 define i32 @test4(ptr %p, ptr %q) {
-; CHECK-LABEL: @test4(ptr %p, ptr %q)
-; CHECK: call i32 @foo(ptr %p), !tbaa [[TAGA:!.*]]
-; CHECK: %c = add i32 %a, %a
+; CHECK-LABEL: define i32 @test4(
+; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA6:![0-9]+]]
+; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
+; CHECK-NEXT:    ret i32 [[C]]
+;
   %a = call i32 @foo(ptr %p), !tbaa !1
   %b = call i32 @foo(ptr %p), !tbaa !0
   %c = add i32 %a, %b
@@ -42,9 +54,12 @@ define i32 @test4(ptr %p, ptr %q) {
 }
 
 define i32 @test5(ptr %p, ptr %q) {
-; CHECK-LABEL: @test5(ptr %p, ptr %q)
-; CHECK: call i32 @foo(ptr %p), !tbaa [[TAGA]]
-; CHECK: %c = add i32 %a, %a
+; CHECK-LABEL: define i32 @test5(
+; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA0]]
+; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
+; CHECK-NEXT:    ret i32 [[C]]
+;
   %a = call i32 @foo(ptr %p), !tbaa !0
   %b = call i32 @foo(ptr %p), !tbaa !1
   %c = add i32 %a, %b
@@ -52,9 +67,12 @@ define i32 @test5(ptr %p, ptr %q) {
 }
 
 define i32 @test6(ptr %p, ptr %q) {
-; CHECK-LABEL: @test6(ptr %p, ptr %q)
-; CHECK: call i32 @foo(ptr %p), !tbaa [[TAGA]]
-; CHECK: %c = add i32 %a, %a
+; CHECK-LABEL: define i32 @test6(
+; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA0]]
+; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
+; CHECK-NEXT:    ret i32 [[C]]
+;
   %a = call i32 @foo(ptr %p), !tbaa !0
   %b = call i32 @foo(ptr %p), !tbaa !3
   %c = add i32 %a, %b
@@ -62,10 +80,12 @@ define i32 @test6(ptr %p, ptr %q) {
 }
 
 define i32 @test7(ptr %p, ptr %q) {
-; CHECK-LABEL: @test7(ptr %p, ptr %q)
-; CHECK: call i32 @foo(ptr %p)
-; CHECK-NOT: tbaa
-; CHECK: %c = add i32 %a, %a
+; CHECK-LABEL: define i32 @test7(
+; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA7:![0-9]+]]
+; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
+; CHECK-NEXT:    ret i32 [[C]]
+;
   %a = call i32 @foo(ptr %p), !tbaa !4
   %b = call i32 @foo(ptr %p), !tbaa !3
   %c = add i32 %a, %b
@@ -73,9 +93,11 @@ define i32 @test7(ptr %p, ptr %q) {
 }
 
 define i32 @test8(ptr %p, ptr %q) {
-; CHECK-LABEL: @test8
-; CHECK-NEXT: store i32 15, ptr %p
-; CHECK-NEXT: ret i32 0
+; CHECK-LABEL: define i32 @test8(
+; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
+; CHECK-NEXT:    store i32 15, ptr [[P]], align 4
+; CHECK-NEXT:    ret i32 0
+;
 ; Since we know the location is invariant, we can forward the
 ; load across the potentially aliasing store.
 
@@ -87,9 +109,11 @@ define i32 @test8(ptr %p, ptr %q) {
 }
 
 define i32 @test9(ptr %p, ptr %q) {
-; CHECK-LABEL: @test9
-; CHECK-NEXT: call void @clobber()
-; CHECK-NEXT: ret i32 0
+; CHECK-LABEL: define i32 @test9(
+; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
+; CHECK-NEXT:    call void @clobber()
+; CHECK-NEXT:    ret i32 0
+;
 ; Since we know the location is invariant, we can forward the
 ; load across the potentially aliasing store (within the call).
 
@@ -103,9 +127,12 @@ define i32 @test9(ptr %p, ptr %q) {
 define i32 @test10(ptr %p, ptr %q) {
 ; If one access encloses the other, then the merged access is the enclosed one
 ; and not just the common final access type.
-; CHECK-LABEL: @test10
-; CHECK: call i32 @foo(ptr %p), !tbaa [[TAG_X_i:!.*]]
-; CHECK: %c = add i32 %a, %a
+; CHECK-LABEL: define i32 @test10(
+; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA10:![0-9]+]]
+; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
+; CHECK-NEXT:    ret i32 [[C]]
+;
   %a = call i32 @foo(ptr %p), !tbaa !15  ; TAG_X_i
   %b = call i32 @foo(ptr %p), !tbaa !19  ; TAG_Y_x_i
   %c = add i32 %a, %b
@@ -115,12 +142,6 @@ define i32 @test10(ptr %p, ptr %q) {
 declare void @clobber()
 declare i32 @foo(ptr) readonly
 
-; CHECK-DAG: [[TAGC]] = !{[[TYPEC:!.*]], [[TYPEC]], i64 0}
-; CHECK-DAG: [[TYPEC]] = !{!"C", [[TYPEA:!.*]]}
-; CHECK-DAG: [[TYPEA]] = !{!"A", !{{.*}}}
-; CHECK-DAG: [[TAGB]] = !{[[TYPEB:!.*]], [[TYPEB]], i64 0}
-; CHECK-DAG: [[TYPEB]] = !{!"B", [[TYPEA]]}
-; CHECK-DAG: [[TAGA]] = !{[[TYPEA]], [[TYPEA]], i64 0}
 !0 = !{!5, !5, i64 0}
 !1 = !{!6, !6, i64 0}
 !2 = !{!"tbaa root"}
@@ -132,9 +153,6 @@ declare i32 @foo(ptr) readonly
 !8 = !{!"another root"}
 !11 = !{!"scalar type", !8}
 
-; CHECK-DAG: [[TAG_X_i]] = !{[[TYPE_X:!.*]], [[TYPE_int:!.*]], i64 0}
-; CHECK-DAG: [[TYPE_X:!.*]] = !{!"struct X", [[TYPE_int]], i64 0}
-; CHECK-DAG: [[TYPE_int]] = !{!"int", {{!.*}}, i64 0}
 !15 = !{!16, !17, i64 0}            ; TAG_X_i
 !16 = !{!"struct X", !17, i64 0}    ; struct X { int i; };
 !17 = !{!"int", !18, i64 0}
@@ -146,3 +164,19 @@ declare i32 @foo(ptr) readonly
 ; A TBAA structure who's only point is to have a constant location.
 !9 = !{!"yet another root"}
 !10 = !{!"node", !9, i64 1}
+;.
+; CHECK: [[TBAA0]] = !{[[META1:![0-9]+]], [[META1]], i64 0}
+; CHECK: [[META1]] = !{!"C", [[META2:![0-9]+]]}
+; CHECK: [[META2]] = !{!"A", [[META3:![0-9]+]]}
+; CHECK: [[META3]] = !{!"tbaa root"}
+; CHECK: [[TBAA4]] = !{[[META5:![0-9]+]], [[META5]], i64 0}
+; CHECK: [[META5]] = !{!"B", [[META2]]}
+; CHECK: [[TBAA6]] = !{[[META2]], [[META2]], i64 0}
+; CHECK: [[TBAA7]] = !{[[META8:![0-9]+]], [[META8]], i64 0}
+; CHECK: [[META8]] = !{!"scalar type", [[META9:![0-9]+]]}
+; CHECK: [[META9]] = !{!"another root"}
+; CHECK: [[TBAA10]] = !{[[META11:![0-9]+]], [[META12:![0-9]+]], i64 0}
+; CHECK: [[META11]] = !{!"struct X", [[META12]], i64 0}
+; CHECK: [[META12]] = !{!"int", [[META13:![0-9]+]], i64 0}
+; CHECK: [[META13]] = !{!"char", [[META3]], i64 0}
+;.
diff --git a/llvm/test/Transforms/JumpThreading/thread-loads.ll b/llvm/test/Transforms/JumpThreading/thread-loads.ll
index 85952e8e6db4f5..6f19b3d17ff1d4 100644
--- a/llvm/test/Transforms/JumpThreading/thread-loads.ll
+++ b/llvm/test/Transforms/JumpThreading/thread-loads.ll
@@ -1,4 +1,4 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals smart
 ; RUN: opt < %s -passes=jump-threading -S | FileCheck %s
 ; RUN: opt < %s -aa-pipeline=basic-aa -passes=jump-threading -S | FileCheck %s
 
@@ -316,13 +316,12 @@ bb3:
   ret i32 %res.0
 }
 
-; Make sure we merge the aliasing metadata. We keep the range metadata for the
-; first load, as it dominates the second load. Hence we can eliminate the
-; branch.
+; We keep the tbaa and range metadata for the first load, as it dominates the
+; second load. Hence we can eliminate the branch.
 define void @test8(ptr, ptr, ptr) {
 ; CHECK-LABEL: @test8(
 ; CHECK-NEXT:  ret2:
-; CHECK-NEXT:    [[A:%.*]] = load i32, ptr [[TMP0:%.*]], align 4, !range [[RNG4:![0-9]+]], !noundef !5
+; CHECK-NEXT:    [[A:%.*]] = load i32, ptr [[TMP0:%.*]], align 4, !tbaa [[TBAA0]], !range [[RNG4:![0-9]+]], !noundef [[META5:![0-9]+]]
 ; CHECK-NEXT:    store i32 [[A]], ptr [[TMP1:%.*]], align 4
 ; CHECK-NEXT:    [[XXX:%.*]] = tail call i32 (...) @f1() #[[ATTR0]]
 ; CHECK-NEXT:    ret void
@@ -455,8 +454,8 @@ define fastcc i32 @Search(i64 %idxprom.i, i64 %idxprom.i89, i32 %c) {
 ; CHECK-NEXT:    [[ARRAYIDX89:%.*]] = getelementptr inbounds [65 x ptr], ptr @last, i64 0, i64 [[IDXPROM_I]]
 ; CHECK-NEXT:    [[PHASE:%.*]] = getelementptr inbounds [65 x %struct.NEXT_MOVE], ptr @next_status, i64 0, i64 [[IDXPROM_I]], i32 0
 ; CHECK-NEXT:    switch i32 [[C:%.*]], label [[CLEANUP:%.*]] [
-; CHECK-NEXT:    i32 1, label [[SW_BB_I:%.*]]
-; CHECK-NEXT:    i32 0, label [[SW_BB21_I:%.*]]
+; CHECK-NEXT:      i32 1, label [[SW_BB_I:%.*]]
+; CHECK-NEXT:      i32 0, label [[SW_BB21_I:%.*]]
 ; CHECK-NEXT:    ]
 ; CHECK:       sw.bb.i:
 ; CHECK-NEXT:    [[CALL_I62:%.*]] = call fastcc ptr @GenerateCheckEvasions()
@@ -680,7 +679,6 @@ right_x:
 }
 
 
-; CHECK: [[RNG4]] = !{i32 0, i32 1}
 
 !0 = !{!3, !3, i64 0}
 !1 = !{!"omnipotent char", !2}
@@ -694,3 +692,11 @@ right_x:
 !9 = !{!7}
 !10 = !{!8}
 !11 = !{}
+;.
+; CHECK: [[TBAA0]] = !{[[META1:![0-9]+]], [[META1]], i64 0}
+; CHECK: [[META1]] = !{!"int", [[META2:![0-9]+]]}
+; CHECK: [[META2]] = !{!"omnipotent char", [[META3:![0-9]+]]}
+; CHECK: [[META3]] = !{!"Simple C/C++ TBAA"}
+; CHECK: [[RNG4]] = !{i32 0, i32 1}
+; CHECK: [[META5]] = !{}
+;.
diff --git a/llvm/test/Transforms/NewGVN/tbaa.ll b/llvm/test/Transforms/NewGVN/tbaa.ll
index 335e782acc8bcd..20c09aa68726a9 100644
--- a/llvm/test/Transforms/NewGVN/tbaa.ll
+++ b/llvm/test/Transforms/NewGVN/tbaa.ll
@@ -4,7 +4,7 @@
 define i32 @test1(ptr %p, ptr %q) {
 ; CHECK-LABEL: define i32 @test1(
 ; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
-; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]])
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA0:![0-9]+]]
 ; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
 ; CHECK-NEXT:    ret i32 [[C]]
 ;
@@ -17,7 +17,7 @@ define i32 @test1(ptr %p, ptr %q) {
 define i32 @test2(ptr %p, ptr %q) {
 ; CHECK-LABEL: define i32 @test2(
 ; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
-; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA0:![0-9]+]]
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA0]]
 ; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
 ; CHECK-NEXT:    ret i32 [[C]]
 ;
@@ -56,7 +56,7 @@ define i32 @test4(ptr %p, ptr %q) {
 define i32 @test5(ptr %p, ptr %q) {
 ; CHECK-LABEL: define i32 @test5(
 ; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
-; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA6]]
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA0]]
 ; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
 ; CHECK-NEXT:    ret i32 [[C]]
 ;
@@ -69,7 +69,7 @@ define i32 @test5(ptr %p, ptr %q) {
 define i32 @test6(ptr %p, ptr %q) {
 ; CHECK-LABEL: define i32 @test6(
 ; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
-; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA6]]
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA0]]
 ; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
 ; CHECK-NEXT:    ret i32 [[C]]
 ;
@@ -82,7 +82,7 @@ define i32 @test6(ptr %p, ptr %q) {
 define i32 @test7(ptr %p, ptr %q) {
 ; CHECK-LABEL: define i32 @test7(
 ; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
-; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]])
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA7:![0-9]+]]
 ; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
 ; CHECK-NEXT:    ret i32 [[C]]
 ;
@@ -129,7 +129,7 @@ define i32 @test10(ptr %p, ptr %q) {
 ; and not just the common final access type.
 ; CHECK-LABEL: define i32 @test10(
 ; CHECK-SAME: ptr [[P:%.*]], ptr [[Q:%.*]]) {
-; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA7:![0-9]+]]
+; CHECK-NEXT:    [[A:%.*]] = call i32 @foo(ptr [[P]]), !tbaa [[TBAA10:![0-9]+]]
 ; CHECK-NEXT:    [[C:%.*]] = add i32 [[A]], [[A]]
 ; CHECK-NEXT:    ret i32 [[C]]
 ;
@@ -172,8 +172,11 @@ declare i32 @foo(ptr) readonly
 ; CHECK: [[TBAA4]] = !{[[META5:![0-9]+]], [[META5]], i64 0}
 ; CHECK: [[META5]] = !{!"B", [[META2]]}
 ; CHECK: [[TBAA6]] = !{[[META2]], [[META2]], i64 0}
-; CHECK: [[TBAA7]] = !{[[META8:![0-9]+]], [[META9:![0-9]+]], i64 0}
-; CHECK: [[META8]] = !{!"struct X", [[META9]], i64 0}
-; CHECK: [[META9]] = !{!"int", [[META10:![0-9]+]], i64 0}
-; CHECK: [[META10]] = !{!"char", [[META3]], i64 0}
+; CHECK: [[TBAA7]] = !{[[META8:![0-9]+]], [[META8]], i64 0}
+; CHECK: [[META8]] = !{!"scalar type", [[META9:![0-9]+]]}
+; CHECK: [[META9]] = !{!"another root"}
+; CHECK: [[TBAA10]] = !{[[META11:![0-9]+]], [[META12:![0-9]+]], i64 0}
+; CHECK: [[META11]] = !{!"struct X", [[META12]], i64 0}
+; CHECK: [[META12]] = !{!"int", [[META13:![0-9]+]], i64 0}
+; CHECK: [[META13]] = !{!"char", [[META3]], i64 0}
 ;.

nikic
nikic approved these changes Nov 18, 2024
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LGTM

@nikic
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nikic commented Nov 18, 2024

Could you please take a look at

llvm-project/llvm/lib/Transforms/Scalar/LICM.cpp

Line 2248 in f14e1a8

PreheaderLoad->setAAMetadata(AATags);
? I think it may currently copy AA metadata from conditional loads to an unconditional load, which may result in issues if we start exploiting UB semantics more.

fhahn added 2 commits November 20, 2024 15:18
@fhahn
[Local] Only intersect tbaa metadata if instr moves.
34c8896 
Preserve tbaa metadata on the replacement instruction, if it does not
move. In that case, the program would be UB, if the aliasing property
encoded in the metadata does not hold.

This makes use of the clarification re tbaa metadata implying UB if the
property does not hold: llvm#116220
@fhahn
!fixup update tests.
0fbe745
@llvmbot llvmbot added the llvm:instcombine Covers the InstCombine, InstSimplify and AggressiveInstCombine passes label Nov 20, 2024
@fhahn fhahn merged commit 0bb1b68 into llvm:main Nov 20, 2024
9 checks passed
@fhahn fhahn deleted the local-tbaa-move branch November 20, 2024 19:31
@nikic
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nikic commented Nov 25, 2024

Do you plan to adjust the noalias/alias.scope logic as well?

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fhahn commented Nov 26, 2024

Yes, will share more PRs soon

fhahn added a commit to fhahn/llvm-project that referenced this pull request Jan 9, 2025
@fhahn
[Local] Only intersect tbaa metadata if instr moves. (llvm#116682)
fb07da1 
Preserve tbaa metadata on the replacement instruction, if it does not
move. In that case, the program would be UB, if the aliasing property
encoded in the metadata does not hold.

This makes use of the clarification re tbaa metadata implying UB if the
property does not hold: llvm#116220

Same as llvm#115868, but for !tbaa

PR: llvm#116682
(cherry picked from commit 0bb1b68)
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llvm:instcombine Covers the InstCombine, InstSimplify and AggressiveInstCombine passes llvm:transforms
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@fhahn @llvmbot @nikic