In Thumb2 mode, lower frame indix references to:
add <rd>, sp, #<imm8>
ldr <rd>, [sp, #<imm8>]
When the offset from sp is multiple of 4 and in range of 0-1020.
This saves code size by utilizing 16-bit instructions.
rdar://9321541
llvm-svn: 129971
diff --git a/llvm/test/CodeGen/Thumb2/2011-04-21-FILoweringBug.ll b/llvm/test/CodeGen/Thumb2/2011-04-21-FILoweringBug.ll
new file mode 100644
index 0000000..604a352
--- /dev/null
+++ b/llvm/test/CodeGen/Thumb2/2011-04-21-FILoweringBug.ll
@@ -0,0 +1,23 @@
+; RUN: llc < %s -mtriple=thumbv7-apple-darwin | FileCheck %s
+
+; Use sp, #imm to lower frame indices when the offset is multiple of 4
+; and in the range of 0-1020. This saves code size by utilizing
+; 16-bit instructions.
+; rdar://9321541
+
+define i32 @t() nounwind {
+entry:
+; CHECK: t:
+; CHECK: sub sp, #12
+; CHECK-NOT: sub
+; CHECK: add r0, sp, #4
+; CHECK: add r1, sp, #8
+; CHECK: mov r2, sp
+ %size = alloca i32, align 4
+ %count = alloca i32, align 4
+ %index = alloca i32, align 4
+ %0 = call i32 @foo(i32* %count, i32* %size, i32* %index) nounwind
+ ret i32 %0
+}
+
+declare i32 @foo(i32*, i32*, i32*)