[llvm] r348215 - [IR] Don't assume all functions are 4 byte aligned
Ranjeet Singh via llvm-commits
llvm-commits at lists.llvm.org
Mon Dec 3 16:01:23 PST 2018
Author: rsingh
Date: Mon Dec 3 16:01:23 2018
New Revision: 348215
URL: http://llvm.org/viewvc/llvm-project?rev=348215&view=rev
Log:
[IR] Don't assume all functions are 4 byte aligned
In some cases different alignments for function might be used to save
space e.g. thumb mode with -Oz will try to use 2 byte function
alignment. Similar patch that fixed this in other areas exists here
https://reviews.llvm.org/D46110
Differential Revision: https://reviews.llvm.org/D55115
Added:
llvm/trunk/test/Analysis/ConstantFolding/func-and-folding.ll
Removed:
llvm/trunk/test/Assembler/2004-03-07-FunctionAddressAlignment.ll
Modified:
llvm/trunk/lib/IR/ConstantFold.cpp
Modified: llvm/trunk/lib/IR/ConstantFold.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/ConstantFold.cpp?rev=348215&r1=348214&r2=348215&view=diff
==============================================================================
--- llvm/trunk/lib/IR/ConstantFold.cpp (original)
+++ llvm/trunk/lib/IR/ConstantFold.cpp Mon Dec 3 16:01:23 2018
@@ -27,6 +27,7 @@
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/Support/ErrorHandling.h"
@@ -1077,10 +1078,8 @@ Constant *llvm::ConstantFoldBinaryInstru
isa<GlobalValue>(CE1->getOperand(0))) {
GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0));
- // Functions are at least 4-byte aligned.
- unsigned GVAlign = GV->getAlignment();
- if (isa<Function>(GV))
- GVAlign = std::max(GVAlign, 4U);
+ unsigned GVAlign =
+ GV->getPointerAlignment(GV->getParent()->getDataLayout());
if (GVAlign > 1) {
unsigned DstWidth = CI2->getType()->getBitWidth();
Added: llvm/trunk/test/Analysis/ConstantFolding/func-and-folding.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ConstantFolding/func-and-folding.ll?rev=348215&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ConstantFolding/func-and-folding.ll (added)
+++ llvm/trunk/test/Analysis/ConstantFolding/func-and-folding.ll Mon Dec 3 16:01:23 2018
@@ -0,0 +1,27 @@
+; RUN: opt < %s -constprop -S -o - | FileCheck %s
+
+; Function Attrs: minsize norecurse nounwind optsize readnone
+define dso_local void @foo1() #0 {
+entry:
+ ret void
+}
+
+; Function Attrs: minsize norecurse nounwind optsize readnone
+define dso_local void @foo2() align 4 {
+entry:
+ ret void
+}
+
+; Function Attrs: minsize nounwind optsize
+define dso_local i32 @main() local_unnamed_addr #1 {
+entry:
+; CHECK: ptrtoint
+ %call = tail call i32 bitcast (i32 (...)* @process to i32 (i32)*)(i32 and (i32 ptrtoint (void ()* @foo1 to i32), i32 2)) #3
+; CHECK-NEXT: ptrtoint
+ %call2 = tail call i32 bitcast (i32 (...)* @process to i32 (i32)*)(i32 and (i32 ptrtoint (void ()* @foo2 to i32), i32 2)) #3
+ ret i32 0
+}
+
+; Function Attrs: minsize optsize
+declare dso_local i32 @process(...) local_unnamed_addr #2
+
Removed: llvm/trunk/test/Assembler/2004-03-07-FunctionAddressAlignment.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Assembler/2004-03-07-FunctionAddressAlignment.ll?rev=348214&view=auto
==============================================================================
--- llvm/trunk/test/Assembler/2004-03-07-FunctionAddressAlignment.ll (original)
+++ llvm/trunk/test/Assembler/2004-03-07-FunctionAddressAlignment.ll (removed)
@@ -1,16 +0,0 @@
-; RUN: llvm-as < %s | llvm-dis | not grep ptrtoint
-; RUN: verify-uselistorder %s
-; All of these should be eliminable
-
-
-define i32 @foo() {
- ret i32 and (i32 ptrtoint (i32()* @foo to i32), i32 1)
-}
-
-define i32 @foo2() {
- ret i32 and (i32 1, i32 ptrtoint (i32()* @foo2 to i32))
-}
-
-define i1 @foo3() {
- ret i1 icmp ne (i1()* @foo3, i1()* null)
-}
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