[clang] [IPSCCP] Variable not visible at Og. (PR #66745)
https://github.com/jryans edited https://github.com/llvm/llvm-project/pull/66745 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [IPSCCP] Variable not visible at Og. (PR #66745)
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
Date: Mon, 18 Sep 2023 12:29:17 +0100
Subject: [PATCH 1/4] [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(GV->user_back());
SI->eraseFromParent();
}
+
+// Try to create a debug constant expression for the glbal variable
+// initializer value.
+SmallVector 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(CV)->getValue();
+std::optional 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(CV)->getValueAPF();
+DIExpression *NewExpr = DIB.createConstantValueExpression(
+APF.bitcastToAPInt().getZExtValue());
+GVEs[0]->replaceOperandWith(1, NewExpr);
+ } else if (Ty->isPointerTy()) {
+if (isa(CV)) {
+ GVEs[0]->replaceOperandWith(1, DIB.createConstantValueExpression(0));
+} else {
+ if (const ConstantExpr *CE = dyn_cast(CV)) {
+if (CE->getNumOperands() == 1) {
+ const Value *V = CE->getOperand(0);
+ const Constant *CV = dyn_cast(V);
+ if (CV && !isa(CV))
+if (const ConstantInt *CI = dyn_cast(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 000..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]] = distin
[clang] [IPSCCP] Variable not visible at Og. (PR #66745)
https://github.com/jryans edited https://github.com/llvm/llvm-project/pull/66745 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [IPSCCP] Variable not visible at Og. (PR #66745)
@@ -106,14 +107,71 @@ static void findReturnsToZap(Function &F,
}
}
-static bool runIPSCCP(
-Module &M, const DataLayout &DL, FunctionAnalysisManager *FAM,
-std::function GetTLI,
-std::function GetTTI,
-std::function GetAC,
-std::function GetDT,
-std::function GetBFI,
-bool IsFuncSpecEnabled) {
+static void createDebugConstantExpression(Module &M, GlobalVariable *GV) {
+ SmallVector GVEs;
+ GV->getDebugInfo(GVEs);
+ if (GVEs.size() != 1)
+return;
+
+ DIBuilder DIB(M);
+
+ // Create integer constant expression.
+ auto createIntegerExpression = [&DIB](const Constant *CV) -> DIExpression * {
+const APInt &API = cast(CV)->getValue();
+std::optional InitIntOpt;
+if (API.isNonNegative())
+ InitIntOpt = API.tryZExtValue();
+else if (auto Temp = API.trySExtValue())
+ // Transform a signed optional to unsigned optional.
+ InitIntOpt = static_cast(*Temp);
felipepiovezan wrote:
Looking at this again, isn't this the equivalent of always doing a sign
extension?
We are basically saying: if this starts with a zero, add zeros; if this starts
with a one, add ones.
Unless I am missing something, this code could be:
```
if (std::optional InitIntOpt = API.trySExtValue())
return DIB.createConstantValueExpression(static_cast(*InitIntOpt))
return nullptr;
```
https://github.com/llvm/llvm-project/pull/66745
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[clang] [IPSCCP] Variable not visible at Og. (PR #66745)
@@ -106,14 +107,71 @@ static void findReturnsToZap(Function &F,
}
}
-static bool runIPSCCP(
-Module &M, const DataLayout &DL, FunctionAnalysisManager *FAM,
-std::function GetTLI,
-std::function GetTTI,
-std::function GetAC,
-std::function GetDT,
-std::function GetBFI,
-bool IsFuncSpecEnabled) {
+static void createDebugConstantExpression(Module &M, GlobalVariable *GV) {
+ SmallVector GVEs;
+ GV->getDebugInfo(GVEs);
+ if (GVEs.size() != 1)
+return;
+
+ DIBuilder DIB(M);
+
+ // Create integer constant expression.
+ auto createIntegerExpression = [&DIB](const Constant *CV) -> DIExpression * {
+const APInt &API = cast(CV)->getValue();
+std::optional InitIntOpt;
+if (API.isNonNegative())
+ InitIntOpt = API.tryZExtValue();
+else if (auto Temp = API.trySExtValue())
+ // Transform a signed optional to unsigned optional.
+ InitIntOpt = static_cast(*Temp);
+return InitIntOpt ? DIB.createConstantValueExpression(InitIntOpt.value())
+ : nullptr;
+ };
+
+ const Constant *CV = GV->getInitializer();
+ Type *Ty = GV->getValueType();
+ if (Ty->isIntegerTy()) {
+DIExpression *InitExpr = createIntegerExpression(CV);
+if (InitExpr)
+ GVEs[0]->replaceOperandWith(1, InitExpr);
+return;
+ }
+
+ if (Ty->isFloatTy() || Ty->isDoubleTy()) {
+const APFloat &APF = cast(CV)->getValueAPF();
+GVEs[0]->replaceOperandWith(1, DIB.createConstantValueExpression(
+ APF.bitcastToAPInt().getZExtValue()));
+return;
+ }
+
+ if (!Ty->isPointerTy())
+return;
+
+ if (isa(CV)) {
+GVEs[0]->replaceOperandWith(1, DIB.createConstantValueExpression(0));
+return;
+ }
+ if (const ConstantExpr *CE = dyn_cast(CV);
+ CE->getNumOperands() == 1) {
+const Value *V = CE->getOperand(0);
+const Constant *CV = dyn_cast(V);
+if (CV && !isa(CV);
felipepiovezan wrote:
Yeah, I believe the intent here would be:
```
if (auto CI = dyn_cast_or_null(V)) {
...
}
```
Note that `!isa(CV)` is not necessary: a global value is always a
pointer, therefore it cannot be a `ConstantInt`
https://github.com/llvm/llvm-project/pull/66745
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[clang] [IPSCCP] Variable not visible at Og. (PR #66745)
@@ -106,14 +107,71 @@ static void findReturnsToZap(Function &F,
}
}
-static bool runIPSCCP(
-Module &M, const DataLayout &DL, FunctionAnalysisManager *FAM,
-std::function GetTLI,
-std::function GetTTI,
-std::function GetAC,
-std::function GetDT,
-std::function GetBFI,
-bool IsFuncSpecEnabled) {
+static void createDebugConstantExpression(Module &M, GlobalVariable *GV) {
+ SmallVector GVEs;
+ GV->getDebugInfo(GVEs);
+ if (GVEs.size() != 1)
+return;
+
+ DIBuilder DIB(M);
+
+ // Create integer constant expression.
+ auto createIntegerExpression = [&DIB](const Constant *CV) -> DIExpression * {
+const APInt &API = cast(CV)->getValue();
+std::optional InitIntOpt;
+if (API.isNonNegative())
+ InitIntOpt = API.tryZExtValue();
+else if (auto Temp = API.trySExtValue())
+ // Transform a signed optional to unsigned optional.
+ InitIntOpt = static_cast(*Temp);
+return InitIntOpt ? DIB.createConstantValueExpression(InitIntOpt.value())
+ : nullptr;
+ };
+
+ const Constant *CV = GV->getInitializer();
+ Type *Ty = GV->getValueType();
+ if (Ty->isIntegerTy()) {
+DIExpression *InitExpr = createIntegerExpression(CV);
+if (InitExpr)
+ GVEs[0]->replaceOperandWith(1, InitExpr);
+return;
+ }
+
+ if (Ty->isFloatTy() || Ty->isDoubleTy()) {
+const APFloat &APF = cast(CV)->getValueAPF();
+GVEs[0]->replaceOperandWith(1, DIB.createConstantValueExpression(
+ APF.bitcastToAPInt().getZExtValue()));
+return;
+ }
+
+ if (!Ty->isPointerTy())
+return;
+
+ if (isa(CV)) {
+GVEs[0]->replaceOperandWith(1, DIB.createConstantValueExpression(0));
+return;
+ }
+ if (const ConstantExpr *CE = dyn_cast(CV);
+ CE->getNumOperands() == 1) {
+const Value *V = CE->getOperand(0);
+const Constant *CV = dyn_cast(V);
+if (CV && !isa(CV);
dwblaikie wrote:
I'm not sure this does what's intended (assuming the intent is that the `CV &&
!isa` part is meant to be part of the boolean condition of the `if` as well as
the `CI` init) - these boolean expressions would have no effect, right? (the
second part of the if, after the semicolon, would be the only condition?
https://github.com/llvm/llvm-project/pull/66745
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[clang] [IPSCCP] Variable not visible at Og. (PR #66745)
@@ -106,14 +107,71 @@ static void findReturnsToZap(Function &F,
}
}
-static bool runIPSCCP(
-Module &M, const DataLayout &DL, FunctionAnalysisManager *FAM,
-std::function GetTLI,
-std::function GetTTI,
-std::function GetAC,
-std::function GetDT,
-std::function GetBFI,
-bool IsFuncSpecEnabled) {
+static void createDebugConstantExpression(Module &M, GlobalVariable *GV) {
+ SmallVector GVEs;
+ GV->getDebugInfo(GVEs);
+ if (GVEs.size() != 1)
+return;
+
+ DIBuilder DIB(M);
+
+ // Create integer constant expression.
+ auto createIntegerExpression = [&DIB](const Constant *CV) -> DIExpression * {
+const APInt &API = cast(CV)->getValue();
+std::optional InitIntOpt;
+if (API.isNonNegative())
+ InitIntOpt = API.tryZExtValue();
+else if (auto Temp = API.trySExtValue())
+ // Transform a signed optional to unsigned optional.
+ InitIntOpt = static_cast(*Temp);
+return InitIntOpt ? DIB.createConstantValueExpression(InitIntOpt.value())
+ : nullptr;
+ };
+
+ const Constant *CV = GV->getInitializer();
+ Type *Ty = GV->getValueType();
+ if (Ty->isIntegerTy()) {
+DIExpression *InitExpr = createIntegerExpression(CV);
+if (InitExpr)
+ GVEs[0]->replaceOperandWith(1, InitExpr);
+return;
+ }
+
+ if (Ty->isFloatTy() || Ty->isDoubleTy()) {
+const APFloat &APF = cast(CV)->getValueAPF();
+GVEs[0]->replaceOperandWith(1, DIB.createConstantValueExpression(
+ APF.bitcastToAPInt().getZExtValue()));
+return;
+ }
+
+ if (!Ty->isPointerTy())
+return;
+
+ if (isa(CV)) {
+GVEs[0]->replaceOperandWith(1, DIB.createConstantValueExpression(0));
+return;
+ }
+ if (const ConstantExpr *CE = dyn_cast(CV);
dwblaikie wrote:
This is probably problematic too - the initializer part of the `if` isn't part
of the boolean condition - so the `CE` would be unconditionally dereferenced in
the `CE->getNumOperands()` call - so either the `CE` init should use `cast`,
not `dyn_cast` - or the condition needs to be `CE && CE->getNumOperands() ...`
(or nested `if`s)
https://github.com/llvm/llvm-project/pull/66745
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[clang] [IPSCCP] Variable not visible at Og: (PR #66745)
@@ -371,6 +372,52 @@ static bool runIPSCCP(
StoreInst *SI = cast(GV->user_back());
SI->eraseFromParent();
}
+
+// Try to create a debug constant expression for the glbal variable
+// initializer value.
+SmallVector 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(CV)->getValue();
+std::optional 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(CV)->getValueAPF();
+DIExpression *NewExpr = DIB.createConstantValueExpression(
+APF.bitcastToAPInt().getZExtValue());
+GVEs[0]->replaceOperandWith(1, NewExpr);
+ } else if (Ty->isPointerTy()) {
+if (isa(CV)) {
+ GVEs[0]->replaceOperandWith(1, DIB.createConstantValueExpression(0));
+} else {
+ if (const ConstantExpr *CE = dyn_cast(CV)) {
+if (CE->getNumOperands() == 1) {
+ const Value *V = CE->getOperand(0);
+ const Constant *CV = dyn_cast(V);
+ if (CV && !isa(CV))
+if (const ConstantInt *CI = dyn_cast(CV))
+ GVEs[0]->replaceOperandWith(1, createIntExpression(CI));
+}
+ }
+}
+ }
+}
CarlosAlbertoEnciso wrote:
Replaced with your suggested change.
https://github.com/llvm/llvm-project/pull/66745
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[clang] [IPSCCP] Variable not visible at Og: (PR #66745)
@@ -371,6 +372,52 @@ static bool runIPSCCP(
StoreInst *SI = cast(GV->user_back());
SI->eraseFromParent();
}
+
+// Try to create a debug constant expression for the glbal variable
+// initializer value.
+SmallVector 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(CV)->getValue();
+std::optional 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(CV)->getValueAPF();
CarlosAlbertoEnciso wrote:
Changed to `cast`
https://github.com/llvm/llvm-project/pull/66745
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[clang] [IPSCCP] Variable not visible at Og: (PR #66745)
@@ -371,6 +372,52 @@ static bool runIPSCCP(
StoreInst *SI = cast(GV->user_back());
SI->eraseFromParent();
}
+
+// Try to create a debug constant expression for the glbal variable
+// initializer value.
+SmallVector 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(CV)->getValue();
+std::optional 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));
CarlosAlbertoEnciso wrote:
The function `replaceOperandWith` takes that into consideration.
https://github.com/llvm/llvm-project/pull/66745
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[clang] [IPSCCP] Variable not visible at Og: (PR #66745)
@@ -371,6 +372,52 @@ static bool runIPSCCP(
StoreInst *SI = cast(GV->user_back());
SI->eraseFromParent();
}
+
+// Try to create a debug constant expression for the glbal variable
+// initializer value.
+SmallVector 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(CV)->getValue();
+std::optional 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());
CarlosAlbertoEnciso wrote:
Changed to use `cast`.
https://github.com/llvm/llvm-project/pull/66745
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[clang] [IPSCCP] Variable not visible at Og: (PR #66745)
@@ -371,6 +372,52 @@ static bool runIPSCCP(
StoreInst *SI = cast(GV->user_back());
SI->eraseFromParent();
}
+
+// Try to create a debug constant expression for the glbal variable
+// initializer value.
+SmallVector 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(CV)->getValue();
+std::optional 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();
CarlosAlbertoEnciso wrote:
Using instead `static_cast`
https://github.com/llvm/llvm-project/pull/66745
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[clang] [IPSCCP] Variable not visible at Og: (PR #66745)
@@ -371,6 +372,52 @@ static bool runIPSCCP( StoreInst *SI = cast(GV->user_back()); SI->eraseFromParent(); } + +// Try to create a debug constant expression for the glbal variable +// initializer value. CarlosAlbertoEnciso wrote: Moving the code to a helper function. https://github.com/llvm/llvm-project/pull/66745 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [IPSCCP] Variable not visible at Og: (PR #66745)
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
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(GV->user_back());
SI->eraseFromParent();
}
+
+// Try to create a debug constant expression for the glbal variable
+// initializer value.
+SmallVector 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(CV)->getValue();
+std::optional 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(CV)->getValueAPF();
+DIExpression *NewExpr = DIB.createConstantValueExpression(
+APF.bitcastToAPInt().getZExtValue());
+GVEs[0]->replaceOperandWith(1, NewExpr);
+ } else if (Ty->isPointerTy()) {
+if (isa(CV)) {
+ GVEs[0]->replaceOperandWith(1, DIB.createConstantValueExpression(0));
+} else {
+ if (const ConstantExpr *CE = dyn_cast(CV)) {
+if (CE->getNumOperands() == 1) {
+ const Value *V = CE->getOperand(0);
+ const Constant *CV = dyn_cast(V);
+ if (CV && !isa(CV))
+if (const ConstantInt *CI = dyn_cast(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 000..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 !
[clang] [IPSCCP] Variable not visible at Og: (PR #66745)
https://github.com/jryans edited https://github.com/llvm/llvm-project/pull/66745 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
