From 57db772581ee01e2bd36a73273dcc977d846f67a Mon Sep 17 00:00:00 2001
From: David Majnemer <david.majnemer@gmail.com>
Date: Fri, 17 Jun 2016 17:47:24 +0000
Subject: [PATCH] [CodeGen] Use pointer-sized integers for ptrtoint sources
Given something like:
void *v = (void *)100;
We need to synthesize a ptrtoint operation from 100. During constant
emission, we choose i64 as the type for our constant because it
guaranteed not to drop any bits from our CharUnits representation of the
value. However, this is suboptimal for 32-bit targets: LLVM passes like
GlobalOpt will get confused by these sorts of casts resulting in
pessimization.
Instead, make sure the ptrtoint operand has a pointer-sized integer
type.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@273020 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/CodeGen/CGExprConstant.cpp | 8 +++++++-
test/CodeGen/const-init.c | 2 +-
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index d64c5876ee2..8ad1a4d29cd 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -1314,8 +1314,14 @@ llvm::Constant *CodeGenModule::EmitConstantValue(const APValue &Value,
// Convert to the appropriate type; this could be an lvalue for
// an integer.
- if (isa<llvm::PointerType>(DestTy))
+ if (isa<llvm::PointerType>(DestTy)) {
+ // Convert the integer to a pointer-sized integer before converting it
+ // to a pointer.
+ C = llvm::ConstantExpr::getIntegerCast(
+ C, getDataLayout().getIntPtrType(DestTy),
+ /*isSigned=*/false);
return llvm::ConstantExpr::getIntToPtr(C, DestTy);
+ }
// If the types don't match this should only be a truncate.
if (C->getType() != DestTy)
diff --git a/test/CodeGen/const-init.c b/test/CodeGen/const-init.c
index 9434f1d1b24..3fd231b630e 100644
--- a/test/CodeGen/const-init.c
+++ b/test/CodeGen/const-init.c
@@ -84,7 +84,7 @@ struct g13_s0 g13[] = {
{ (long) &g12_tmp }
};
-// CHECK: @g14 = global i8* inttoptr (i64 100 to i8*)
+// CHECK: @g14 = global i8* inttoptr (i32 100 to i8*)
void *g14 = (void*) 100;
// CHECK: @g15 = global i32 -1
--
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