From 9630a9999b43bc3fc3ac87710540aed0f451c721 Mon Sep 17 00:00:00 2001
From: luxufan <luxufan@iscas.ac.cn>
Date: Sun, 26 Mar 2023 22:25:21 +0800
Subject: [PATCH] [Local] Preserve !nonnull only when K dominate J and K has a
 !noundef

Similar to D142687

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D146799
---
 llvm/lib/Transforms/Utils/Local.cpp                |  3 +-
 .../InstCombine/load-combine-metadata-dominance.ll | 45 +++++++++++++++++++++-
 llvm/test/Transforms/NewGVN/metadata-nonnull.ll    |  6 +--
 3 files changed, 47 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 848db3f..c7b1dc9 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -2686,8 +2686,7 @@ void llvm::combineMetadata(Instruction *K, const Instruction *J,
         K->setMetadata(Kind, JMD);
         break;
       case LLVMContext::MD_nonnull:
-        // If K does move, keep nonull if it is present in both instructions.
-        if (DoesKMove)
+        if (DoesKMove || !K->hasMetadata(LLVMContext::MD_noundef))
           K->setMetadata(Kind, JMD);
         break;
       case LLVMContext::MD_invariant_group:
diff --git a/llvm/test/Transforms/InstCombine/load-combine-metadata-dominance.ll b/llvm/test/Transforms/InstCombine/load-combine-metadata-dominance.ll
index 4949b00..5f86c16 100644
--- a/llvm/test/Transforms/InstCombine/load-combine-metadata-dominance.ll
+++ b/llvm/test/Transforms/InstCombine/load-combine-metadata-dominance.ll
@@ -3,14 +3,14 @@
 
 target datalayout = "e-m:e-p:64:64:64-i64:64-f80:128-n8:16:32:64-S128"
 
-; Check that nonnull metadata is propagated from dominating load.
+; Check that nonnull metadata is not propagated from dominating load.
 define void @combine_metadata_dominance1(ptr %p) {
 ; CHECK-LABEL: define void @combine_metadata_dominance1
 ; CHECK-SAME: (ptr [[P:%.*]]) {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[BB1:%.*]]
 ; CHECK:       bb1:
-; CHECK-NEXT:    [[A:%.*]] = load ptr, ptr [[P]], align 8, !nonnull !0
+; CHECK-NEXT:    [[A:%.*]] = load ptr, ptr [[P]], align 8
 ; CHECK-NEXT:    store i32 0, ptr [[A]], align 4
 ; CHECK-NEXT:    ret void
 ;
@@ -55,5 +55,46 @@ bb2:
   ret void
 }
 
+define void @combine_metadata_dominance3(ptr %p) {
+; CHECK-LABEL: define void @combine_metadata_dominance3
+; CHECK-SAME: (ptr [[P:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[BB1:%.*]]
+; CHECK:       bb1:
+; CHECK-NEXT:    [[A:%.*]] = load ptr, ptr [[P]], align 8, !nonnull !0, !noundef !0
+; CHECK-NEXT:    store i32 0, ptr [[A]], align 4
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = load ptr, ptr %p, !nonnull !0, !noundef !1
+  br label %bb1
+
+bb1:
+  %b = load ptr, ptr %p
+  store i32 0, ptr %a
+  store i32 0, ptr %b
+  ret void
+}
+
+define void @combine_metadata_dominance4(ptr %p) {
+; CHECK-LABEL: define void @combine_metadata_dominance4
+; CHECK-SAME: (ptr [[P:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[BB1:%.*]]
+; CHECK:       bb1:
+; CHECK-NEXT:    [[A:%.*]] = load ptr, ptr [[P]], align 8
+; CHECK-NEXT:    store i32 0, ptr [[A]], align 4
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = load ptr, ptr %p, !nonnull !0
+  br label %bb1
 
+bb1:
+  %b = load ptr, ptr %p, !noundef !1
+  store i32 0, ptr %a
+  store i32 0, ptr %b
+  ret void
+}
 !0 = !{}
+!1 = !{}
diff --git a/llvm/test/Transforms/NewGVN/metadata-nonnull.ll b/llvm/test/Transforms/NewGVN/metadata-nonnull.ll
index d76d46e..cd0922f 100644
--- a/llvm/test/Transforms/NewGVN/metadata-nonnull.ll
+++ b/llvm/test/Transforms/NewGVN/metadata-nonnull.ll
@@ -7,7 +7,7 @@ define ptr @test1(ptr %v0, ptr %v1) {
 ; CHECK-LABEL: define ptr @test1
 ; CHECK-SAME: (ptr [[V0:%.*]], ptr [[V1:%.*]]) {
 ; CHECK-NEXT:  top:
-; CHECK-NEXT:    [[V2:%.*]] = load ptr, ptr [[V0]], align 8, !nonnull !0
+; CHECK-NEXT:    [[V2:%.*]] = load ptr, ptr [[V0]], align 8
 ; CHECK-NEXT:    store ptr [[V2]], ptr [[V1]], align 8
 ; CHECK-NEXT:    ret ptr [[V2]]
 ;
@@ -92,7 +92,7 @@ define ptr @test5(ptr %v0) {
 ; CHECK-LABEL: define ptr @test5
 ; CHECK-SAME: (ptr [[V0:%.*]]) {
 ; CHECK-NEXT:  top:
-; CHECK-NEXT:    [[V1:%.*]] = load ptr, ptr [[V0]], align 8, !nonnull !0
+; CHECK-NEXT:    [[V1:%.*]] = load ptr, ptr [[V0]], align 8
 ; CHECK-NEXT:    call void @use1(ptr [[V1]])
 ; CHECK-NEXT:    br i1 undef, label [[BB1:%.*]], label [[BB2:%.*]]
 ; CHECK:       bb1:
@@ -120,7 +120,7 @@ define ptr @test6(ptr %v0, ptr %v1) {
 ; CHECK-NEXT:  top:
 ; CHECK-NEXT:    br i1 undef, label [[BB1:%.*]], label [[BB2:%.*]]
 ; CHECK:       bb1:
-; CHECK-NEXT:    [[V2:%.*]] = load ptr, ptr [[V0]], align 8, !nonnull !0
+; CHECK-NEXT:    [[V2:%.*]] = load ptr, ptr [[V0]], align 8
 ; CHECK-NEXT:    store ptr [[V2]], ptr [[V1]], align 8
 ; CHECK-NEXT:    ret ptr [[V2]]
 ; CHECK:       bb2:
-- 
2.7.4