From: Cameron Zwarich <zwarich@apple.com>
Date: Wed, 29 Jun 2011 22:24:25 +0000 (+0000)
Subject: In the ARM global merging pass, allow extraneous alignment specifiers. This pass
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=faff12731968c2d3f1ff56a43749d27e1696aafa

In the ARM global merging pass, allow extraneous alignment specifiers. This pass
already makes the assumption, which is correct on ARM, that a type's alignment is
less than its alloc size. This improves codegen with Clang (which inserts a lot of
extraneous alignment specifiers) and fixes <rdar://problem/9695089>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134106 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/ARM/ARMGlobalMerge.cpp b/lib/Target/ARM/ARMGlobalMerge.cpp
index 3f0238387a2..4bdd4f12d76 100644
--- a/lib/Target/ARM/ARMGlobalMerge.cpp
+++ b/lib/Target/ARM/ARMGlobalMerge.cpp
@@ -175,7 +175,9 @@ bool ARMGlobalMerge::doInitialization(Module &M) {
       continue;
 
     // Ignore fancy-aligned globals for now.
-    if (I->getAlignment() != 0)
+    unsigned Alignment = I->getAlignment();
+    unsigned AllocSize = TD->getTypeAllocSize(I->getType()->getElementType());
+    if (Alignment > AllocSize)
       continue;
 
     // Ignore all 'special' globals.
@@ -183,7 +185,7 @@ bool ARMGlobalMerge::doInitialization(Module &M) {
         I->getName().startswith(".llvm."))
       continue;
 
-    if (TD->getTypeAllocSize(I->getType()->getElementType()) < MaxOffset) {
+    if (AllocSize < MaxOffset) {
       const TargetLoweringObjectFile &TLOF = TLI->getObjFileLowering();
       if (TLOF.getKindForGlobal(I, TLI->getTargetMachine()).isBSSLocal())
         BSSGlobals.push_back(I);
diff --git a/test/CodeGen/ARM/2011-06-29-MergeGlobalsAlign.ll b/test/CodeGen/ARM/2011-06-29-MergeGlobalsAlign.ll
new file mode 100644
index 00000000000..1b5b8a99c2e
--- /dev/null
+++ b/test/CodeGen/ARM/2011-06-29-MergeGlobalsAlign.ll
@@ -0,0 +1,12 @@
+; RUN: llc < %s -mtriple=thumbv7-apple-darwin10 | FileCheck %s
+; CHECK: .zerofill __DATA,__bss,__MergedGlobals,16,2
+
+%struct.config = type { i16, i16, i16, i16 }
+
+@prev = external global [0 x i16]
+@max_lazy_match = internal unnamed_addr global i32 0, align 4
+@read_buf = external global i32 (i8*, i32)*
+@window = external global [0 x i8]
+@lookahead = internal unnamed_addr global i32 0, align 4
+@eofile.b = internal unnamed_addr global i1 false
+@ins_h = internal unnamed_addr global i32 0, align 4