[GlobalMerge] Take into account minsize on Global users' parents.

Now that we can look at users, we can trivially do this: when we would
have otherwise disabled GlobalMerge (currently -O<3), we can just run
it for minsize functions, as it's usually a codesize win.

Differential Revision: http://reviews.llvm.org/D10054

llvm-svn: 239087

1 files changed, 74 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/AArch64/global-merge-ignore-single-use-minsize.ll b/llvm/test/CodeGen/AArch64/global-merge-ignore-single-use-minsize.ll
new file mode 100644
index 00000000000..e83cbab140a
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/global-merge-ignore-single-use-minsize.ll
@@ -0,0 +1,74 @@
+; RUN: llc -mtriple=aarch64-apple-ios -asm-verbose=false -aarch64-collect-loh=false \
+; RUN:   -O1 -global-merge-group-by-use -global-merge-ignore-single-use \
+; RUN:   %s -o - | FileCheck %s
+
+; Check that, at -O1, we only merge globals used in minsize functions.
+; We assume that globals of the same size aren't reordered inside a set.
+; We use -global-merge-ignore-single-use, and thus only expect one merged set.
+
+@m1 = internal global i32 0, align 4
+@n1 = internal global i32 0, align 4
+
+; CHECK-LABEL: f1:
+define void @f1(i32 %a1, i32 %a2) minsize nounwind {
+; CHECK-NEXT: adrp x8, [[SET:__MergedGlobals]]@PAGE
+; CHECK-NEXT: add x8, x8, [[SET]]@PAGEOFF
+; CHECK-NEXT: stp w0, w1, [x8]
+; CHECK-NEXT: ret
+  store i32 %a1, i32* @m1, align 4
+  store i32 %a2, i32* @n1, align 4
+  ret void
+}
+
+@m2 = internal global i32 0, align 4
+@n2 = internal global i32 0, align 4
+
+; CHECK-LABEL: f2:
+define void @f2(i32 %a1, i32 %a2) nounwind {
+; CHECK-NEXT: adrp x8, _m2@PAGE
+; CHECK-NEXT: adrp x9, _n2@PAGE
+; CHECK-NEXT: str w0, [x8, _m2@PAGEOFF]
+; CHECK-NEXT: str w1, [x9, _n2@PAGEOFF]
+; CHECK-NEXT: ret
+  store i32 %a1, i32* @m2, align 4
+  store i32 %a2, i32* @n2, align 4
+  ret void
+}
+
+; If we have use sets partially overlapping between a minsize and a non-minsize
+; function, explicitly check that we only consider the globals used in the
+; minsize function for merging.
+
+@m3 = internal global i32 0, align 4
+@n3 = internal global i32 0, align 4
+
+; CHECK-LABEL: f3:
+define void @f3(i32 %a1, i32 %a2) minsize nounwind {
+; CHECK-NEXT: adrp x8, [[SET]]@PAGE
+; CHECK-NEXT: add x8, x8, [[SET]]@PAGEOFF
+; CHECK-NEXT: stp w0, w1, [x8, #8]
+; CHECK-NEXT: ret
+  store i32 %a1, i32* @m3, align 4
+  store i32 %a2, i32* @n3, align 4
+  ret void
+}
+
+@n4 = internal global i32 0, align 4
+
+; CHECK-LABEL: f4:
+define void @f4(i32 %a1, i32 %a2) nounwind {
+; CHECK-NEXT: adrp x8, [[SET]]@PAGE
+; CHECK-NEXT: add x8, x8, [[SET]]@PAGEOFF
+; CHECK-NEXT: adrp x9, _n4@PAGE
+; CHECK-NEXT: str w0, [x8, #8]
+; CHECK-NEXT: str w1, [x9, _n4@PAGEOFF]
+; CHECK-NEXT: ret
+  store i32 %a1, i32* @m3, align 4
+  store i32 %a2, i32* @n4, align 4
+  ret void
+}
+
+; CHECK-DAG: .zerofill __DATA,__bss,[[SET]],16,3
+; CHECK-DAG: .zerofill __DATA,__bss,_m2,4,2
+; CHECK-DAG: .zerofill __DATA,__bss,_n2,4,2
+; CHECK-DAG: .zerofill __DATA,__bss,_n4,4,2