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 3f0238387a2ba2d0972b317686fdfaeb5e73b1df..4bdd4f12d76c4503b9ffae94d66e9f32a14d6a44 100644 (file)
--- 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.
       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.
       continue;
 
     // Ignore all 'special' globals.


@@ -183,7 +185,7 @@ bool ARMGlobalMerge::doInitialization(Module &M) {
         I->getName().startswith(".llvm."))
       continue;
 
         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);
       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 (file)
index 0000000..1b5b8a9
--- /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