[clang-tools-extra] [IPSCCP] Variable not visible at Og: (PR #66745)
Carlos Alberto Enciso via cfe-commits
cfe-commits at lists.llvm.org
Tue Oct 3 06:40:32 PDT 2023
https://github.com/CarlosAlbertoEnciso updated https://github.com/llvm/llvm-project/pull/66745
>From b24943f63025822a5c5ba90c4a7b47f7123ec4db Mon Sep 17 00:00:00 2001
From: Carlos Alberto Enciso <carlos.alberto.enciso at gmail.com>
Date: Mon, 18 Sep 2023 12:29:17 +0100
Subject: [PATCH] [IPSCCP] Variable not visible at Og:
https://bugs.llvm.org/show_bug.cgi?id=51559
https://github.com/llvm/llvm-project/issues/50901
IPSCCP pass removes the global variable and does not
create a constant expression for the initializer value.
---
llvm/lib/Transforms/IPO/SCCP.cpp | 47 +++++++
llvm/test/Transforms/SCCP/pr50901.ll | 184 +++++++++++++++++++++++++++
2 files changed, 231 insertions(+)
create mode 100644 llvm/test/Transforms/SCCP/pr50901.ll
diff --git a/llvm/lib/Transforms/IPO/SCCP.cpp b/llvm/lib/Transforms/IPO/SCCP.cpp
index 84f5bbf7039416b..e09769e00148143 100644
--- a/llvm/lib/Transforms/IPO/SCCP.cpp
+++ b/llvm/lib/Transforms/IPO/SCCP.cpp
@@ -22,6 +22,7 @@
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/AttributeMask.h"
#include "llvm/IR/Constants.h"
+#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ModRef.h"
@@ -371,6 +372,52 @@ static bool runIPSCCP(
StoreInst *SI = cast<StoreInst>(GV->user_back());
SI->eraseFromParent();
}
+
+ // Try to create a debug constant expression for the glbal variable
+ // initializer value.
+ SmallVector<DIGlobalVariableExpression *, 1> GVEs;
+ GV->getDebugInfo(GVEs);
+ if (GVEs.size() == 1) {
+ DIBuilder DIB(M);
+
+ // Create integer constant expression.
+ auto createIntExpression = [&DIB](const Constant *CV) -> DIExpression * {
+ const APInt &API = dyn_cast<ConstantInt>(CV)->getValue();
+ std::optional<uint64_t> InitIntOpt;
+ if (API.isNonNegative())
+ InitIntOpt = API.tryZExtValue();
+ else if (auto Temp = API.trySExtValue(); Temp.has_value())
+ // Transform a signed optional to unsigned optional.
+ InitIntOpt = (uint64_t)Temp.value();
+ return DIB.createConstantValueExpression(InitIntOpt.value());
+ };
+
+ const Constant *CV = GV->getInitializer();
+ Type *Ty = GV->getValueType();
+ if (Ty->isIntegerTy()) {
+ GVEs[0]->replaceOperandWith(1, createIntExpression(CV));
+ } else if (Ty->isFloatTy() || Ty->isDoubleTy()) {
+ const APFloat &APF = dyn_cast<ConstantFP>(CV)->getValueAPF();
+ DIExpression *NewExpr = DIB.createConstantValueExpression(
+ APF.bitcastToAPInt().getZExtValue());
+ GVEs[0]->replaceOperandWith(1, NewExpr);
+ } else if (Ty->isPointerTy()) {
+ if (isa<ConstantPointerNull>(CV)) {
+ GVEs[0]->replaceOperandWith(1, DIB.createConstantValueExpression(0));
+ } else {
+ if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
+ if (CE->getNumOperands() == 1) {
+ const Value *V = CE->getOperand(0);
+ const Constant *CV = dyn_cast<Constant>(V);
+ if (CV && !isa<GlobalValue>(CV))
+ if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
+ GVEs[0]->replaceOperandWith(1, createIntExpression(CI));
+ }
+ }
+ }
+ }
+ }
+
MadeChanges = true;
M.eraseGlobalVariable(GV);
++NumGlobalConst;
diff --git a/llvm/test/Transforms/SCCP/pr50901.ll b/llvm/test/Transforms/SCCP/pr50901.ll
new file mode 100644
index 000000000000000..56961d2e32db41c
--- /dev/null
+++ b/llvm/test/Transforms/SCCP/pr50901.ll
@@ -0,0 +1,184 @@
+; RUN: opt -passes=ipsccp -S -o - < %s | FileCheck %s
+
+; Global variables g_11, g_22, g_33, g_44, g_55, g_66 and g_77
+; are not visible in the debugger.
+
+; 1 int g_1 = -4;
+; 2 float g_2 = 4.44;
+; 3 char g_3 = 'a';
+; 4 unsigned g_4 = 4;
+; 5 bool g_5 = true;
+; 6 int *g_6 = nullptr;
+; 7 float *g_7 = nullptr;
+; 8
+; 9 static int g_11 = -5;
+; 10 static float g_22 = 5.55;
+; 11 static char g_33 = 'b';
+; 12 static unsigned g_44 = 5;
+; 13 static bool g_55 = true;
+; 14 static int *g_66 = nullptr;
+; 15 static float *g_77 = (float *)(55 + 15);
+; 16
+; 17 void bar() {
+; 18 g_1 = g_11;
+; 19 g_2 = g_22;
+; 20 g_3 = g_33;
+; 21 g_4 = g_44;
+; 22 g_5 = g_55;
+; 23 g_6 = g_66;
+; 24 g_7 = g_77;
+; 25 }
+; 26
+; 27 int main() {
+; 28 {
+; 29 bar();
+; 30 }
+; 31 }
+
+; CHECK: ![[G1:[0-9]+]] = !DIGlobalVariableExpression(var: ![[DBG1:[0-9]+]], expr: !DIExpression(DW_OP_constu, 18446744073709551611, DW_OP_stack_value))
+; CHECK-DAG: ![[DBG1]] = distinct !DIGlobalVariable(name: "g_11", {{.*}}
+; CHECK: ![[G2:[0-9]+]] = !DIGlobalVariableExpression(var: ![[DBG2:[0-9]+]], expr: !DIExpression(DW_OP_constu, 1085381018, DW_OP_stack_value))
+; CHECK-DAG: ![[DBG2]] = distinct !DIGlobalVariable(name: "g_22", {{.*}}
+; CHECK: ![[G3:[0-9]+]] = !DIGlobalVariableExpression(var: ![[DBG3:[0-9]+]], expr: !DIExpression(DW_OP_constu, 98, DW_OP_stack_value))
+; CHECK-DAG: ![[DBG3]] = distinct !DIGlobalVariable(name: "g_33", {{.*}}
+; CHECK: ![[G4:[0-9]+]] = !DIGlobalVariableExpression(var: ![[DBG4:[0-9]+]], expr: !DIExpression(DW_OP_constu, 5, DW_OP_stack_value))
+; CHECK-DAG: ![[DBG4]] = distinct !DIGlobalVariable(name: "g_44", {{.*}}
+; CHECK: ![[G5:[0-9]+]] = !DIGlobalVariableExpression(var: ![[DBG5:[0-9]+]], expr: !DIExpression(DW_OP_constu, 1, DW_OP_stack_value))
+; CHECK-DAG: ![[DBG5]] = distinct !DIGlobalVariable(name: "g_55", {{.*}}
+; CHECK: ![[G6:[0-9]+]] = !DIGlobalVariableExpression(var: ![[DBG6:[0-9]+]], expr: !DIExpression(DW_OP_constu, 0, DW_OP_stack_value))
+; CHECK-DAG: ![[DBG6]] = distinct !DIGlobalVariable(name: "g_66", {{.*}}
+; CHECK: ![[G7:[0-9]+]] = !DIGlobalVariableExpression(var: ![[DBG7:[0-9]+]], expr: !DIExpression(DW_OP_constu, 70, DW_OP_stack_value))
+; CHECK-DAG: ![[DBG7]] = distinct !DIGlobalVariable(name: "g_77", {{.*}}
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-linux-gnu"
+
+ at g_1 = dso_local global i32 -4, align 4, !dbg !0
+ at g_2 = dso_local global float 0x4011C28F60000000, align 4, !dbg !8
+ at g_3 = dso_local global i8 97, align 1, !dbg !10
+ at g_4 = dso_local global i32 4, align 4, !dbg !13
+ at g_5 = dso_local global i8 1, align 1, !dbg !16
+ at g_6 = dso_local global ptr null, align 8, !dbg !19
+ at g_7 = dso_local global ptr null, align 8, !dbg !23
+ at _ZL4g_11 = internal global i32 -5, align 4, !dbg !25
+ at _ZL4g_22 = internal global float 0x4016333340000000, align 4, !dbg !27
+ at _ZL4g_33 = internal global i8 98, align 1, !dbg !29
+ at _ZL4g_44 = internal global i32 5, align 4, !dbg !31
+ at _ZL4g_55 = internal global i8 1, align 1, !dbg !33
+ at _ZL4g_66 = internal global ptr null, align 8, !dbg !35
+ at _ZL4g_77 = internal global ptr inttoptr (i64 70 to ptr), align 8, !dbg !37
+
+define dso_local void @_Z3barv() !dbg !46 {
+entry:
+ %0 = load i32, ptr @_ZL4g_11, align 4, !dbg !49, !tbaa !50
+ store i32 %0, ptr @g_1, align 4, !dbg !54, !tbaa !50
+ %1 = load float, ptr @_ZL4g_22, align 4, !dbg !55, !tbaa !56
+ store float %1, ptr @g_2, align 4, !dbg !58, !tbaa !56
+ %2 = load i8, ptr @_ZL4g_33, align 1, !dbg !59, !tbaa !60
+ store i8 %2, ptr @g_3, align 1, !dbg !61, !tbaa !60
+ %3 = load i32, ptr @_ZL4g_44, align 4, !dbg !62, !tbaa !50
+ store i32 %3, ptr @g_4, align 4, !dbg !63, !tbaa !50
+ %4 = load i8, ptr @_ZL4g_55, align 1, !dbg !64, !tbaa !65, !range !67, !noundef !68
+ %tobool = trunc i8 %4 to i1, !dbg !64
+ %frombool = zext i1 %tobool to i8, !dbg !69
+ store i8 %frombool, ptr @g_5, align 1, !dbg !69, !tbaa !65
+ %5 = load ptr, ptr @_ZL4g_66, align 8, !dbg !70, !tbaa !71
+ store ptr %5, ptr @g_6, align 8, !dbg !73, !tbaa !71
+ %6 = load ptr, ptr @_ZL4g_77, align 8, !dbg !74, !tbaa !71
+ store ptr %6, ptr @g_7, align 8, !dbg !75, !tbaa !71
+ ret void, !dbg !76
+}
+
+define dso_local noundef i32 @main() !dbg !77 {
+entry:
+ call void @_Z3barv(), !dbg !80
+ ret i32 0, !dbg !82
+}
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!39, !40, !41, !42, !43, !44}
+!llvm.ident = !{!45}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "g_1", scope: !2, file: !3, line: 1, type: !22, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, producer: "clang version 18.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, retainedTypes: !4, globals: !7, splitDebugInlining: false, nameTableKind: None)
+!3 = !DIFile(filename: "test.cpp", directory: "")
+!4 = !{!5}
+!5 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !6, size: 64)
+!6 = !DIBasicType(name: "float", size: 32, encoding: DW_ATE_float)
+!7 = !{!0, !8, !10, !13, !16, !19, !23, !25, !27, !29, !31, !33, !35, !37}
+!8 = !DIGlobalVariableExpression(var: !9, expr: !DIExpression())
+!9 = distinct !DIGlobalVariable(name: "g_2", scope: !2, file: !3, line: 2, type: !6, isLocal: false, isDefinition: true)
+!10 = !DIGlobalVariableExpression(var: !11, expr: !DIExpression())
+!11 = distinct !DIGlobalVariable(name: "g_3", scope: !2, file: !3, line: 3, type: !12, isLocal: false, isDefinition: true)
+!12 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+!13 = !DIGlobalVariableExpression(var: !14, expr: !DIExpression())
+!14 = distinct !DIGlobalVariable(name: "g_4", scope: !2, file: !3, line: 4, type: !15, isLocal: false, isDefinition: true)
+!15 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
+!16 = !DIGlobalVariableExpression(var: !17, expr: !DIExpression())
+!17 = distinct !DIGlobalVariable(name: "g_5", scope: !2, file: !3, line: 5, type: !18, isLocal: false, isDefinition: true)
+!18 = !DIBasicType(name: "bool", size: 8, encoding: DW_ATE_boolean)
+!19 = !DIGlobalVariableExpression(var: !20, expr: !DIExpression())
+!20 = distinct !DIGlobalVariable(name: "g_6", scope: !2, file: !3, line: 6, type: !21, isLocal: false, isDefinition: true)
+!21 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !22, size: 64)
+!22 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!23 = !DIGlobalVariableExpression(var: !24, expr: !DIExpression())
+!24 = distinct !DIGlobalVariable(name: "g_7", scope: !2, file: !3, line: 7, type: !5, isLocal: false, isDefinition: true)
+!25 = !DIGlobalVariableExpression(var: !26, expr: !DIExpression())
+!26 = distinct !DIGlobalVariable(name: "g_11", linkageName: "_ZL4g_11", scope: !2, file: !3, line: 9, type: !22, isLocal: true, isDefinition: true)
+!27 = !DIGlobalVariableExpression(var: !28, expr: !DIExpression())
+!28 = distinct !DIGlobalVariable(name: "g_22", linkageName: "_ZL4g_22", scope: !2, file: !3, line: 10, type: !6, isLocal: true, isDefinition: true)
+!29 = !DIGlobalVariableExpression(var: !30, expr: !DIExpression())
+!30 = distinct !DIGlobalVariable(name: "g_33", linkageName: "_ZL4g_33", scope: !2, file: !3, line: 11, type: !12, isLocal: true, isDefinition: true)
+!31 = !DIGlobalVariableExpression(var: !32, expr: !DIExpression())
+!32 = distinct !DIGlobalVariable(name: "g_44", linkageName: "_ZL4g_44", scope: !2, file: !3, line: 12, type: !15, isLocal: true, isDefinition: true)
+!33 = !DIGlobalVariableExpression(var: !34, expr: !DIExpression())
+!34 = distinct !DIGlobalVariable(name: "g_55", linkageName: "_ZL4g_55", scope: !2, file: !3, line: 13, type: !18, isLocal: true, isDefinition: true)
+!35 = !DIGlobalVariableExpression(var: !36, expr: !DIExpression())
+!36 = distinct !DIGlobalVariable(name: "g_66", linkageName: "_ZL4g_66", scope: !2, file: !3, line: 14, type: !21, isLocal: true, isDefinition: true)
+!37 = !DIGlobalVariableExpression(var: !38, expr: !DIExpression())
+!38 = distinct !DIGlobalVariable(name: "g_77", linkageName: "_ZL4g_77", scope: !2, file: !3, line: 15, type: !5, isLocal: true, isDefinition: true)
+!39 = !{i32 7, !"Dwarf Version", i32 5}
+!40 = !{i32 2, !"Debug Info Version", i32 3}
+!41 = !{i32 1, !"wchar_size", i32 4}
+!42 = !{i32 8, !"PIC Level", i32 2}
+!43 = !{i32 7, !"PIE Level", i32 2}
+!44 = !{i32 7, !"uwtable", i32 2}
+!45 = !{!"clang version 18.0.0"}
+!46 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !3, file: !3, line: 17, type: !47, scopeLine: 17, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2)
+!47 = !DISubroutineType(types: !48)
+!48 = !{null}
+!49 = !DILocation(line: 18, column: 9, scope: !46)
+!50 = !{!51, !51, i64 0}
+!51 = !{!"int", !52, i64 0}
+!52 = !{!"omnipotent char", !53, i64 0}
+!53 = !{!"Simple C++ TBAA"}
+!54 = !DILocation(line: 18, column: 7, scope: !46)
+!55 = !DILocation(line: 19, column: 9, scope: !46)
+!56 = !{!57, !57, i64 0}
+!57 = !{!"float", !52, i64 0}
+!58 = !DILocation(line: 19, column: 7, scope: !46)
+!59 = !DILocation(line: 20, column: 9, scope: !46)
+!60 = !{!52, !52, i64 0}
+!61 = !DILocation(line: 20, column: 7, scope: !46)
+!62 = !DILocation(line: 21, column: 9, scope: !46)
+!63 = !DILocation(line: 21, column: 7, scope: !46)
+!64 = !DILocation(line: 22, column: 9, scope: !46)
+!65 = !{!66, !66, i64 0}
+!66 = !{!"bool", !52, i64 0}
+!67 = !{i8 0, i8 2}
+!68 = !{}
+!69 = !DILocation(line: 22, column: 7, scope: !46)
+!70 = !DILocation(line: 23, column: 9, scope: !46)
+!71 = !{!72, !72, i64 0}
+!72 = !{!"any pointer", !52, i64 0}
+!73 = !DILocation(line: 23, column: 7, scope: !46)
+!74 = !DILocation(line: 24, column: 9, scope: !46)
+!75 = !DILocation(line: 24, column: 7, scope: !46)
+!76 = !DILocation(line: 25, column: 1, scope: !46)
+!77 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 27, type: !78, scopeLine: 27, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2)
+!78 = !DISubroutineType(types: !79)
+!79 = !{!22}
+!80 = !DILocation(line: 29, column: 5, scope: !81)
+!81 = distinct !DILexicalBlock(scope: !77, file: !3, line: 28, column: 3)
+!82 = !DILocation(line: 31, column: 1, scope: !77)
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