Improve handling of stack accesses in Thumb-1

Thumb-1 only allows SP-based LDR and STR to be word-sized, and SP-base LDR,
STR, and ADD only allow offsets that are a multiple of 4. Make some changes
to better make use of these instructions:

* Use word loads for anyext byte and halfword loads from the stack.
* Enforce 4-byte alignment on objects accessed in this way, to ensure that
  the offset is valid.
* Do the same for objects whose frame index is used, in order to avoid having
  to use more than one ADD to generate the frame index.
* Correct how many bits of offset we think AddrModeT1_s has.

Patch by John Brawn.

llvm-svn: 230496

1 files changed, 3 insertions, 3 deletions

diff --git a/llvm/test/CodeGen/ARM/frame-register.ll b/llvm/test/CodeGen/ARM/frame-register.ll
index e6a55bddaf1..b04e376693d 100644
--- a/llvm/test/CodeGen/ARM/frame-register.ll
+++ b/llvm/test/CodeGen/ARM/frame-register.ll
@@ -30,9 +30,9 @@ entry:
 ; CHECK-ARM: push {r11, lr}
 ; CHECK-ARM: mov r11, sp
 
-; CHECK-THUMB: push {r4, r6, r7, lr}
-; CHECK-THUMB: add r7, sp, #8
+; CHECK-THUMB: push {r7, lr}
+; CHECK-THUMB: add r7, sp, #0
 
 ; CHECK-DARWIN-ARM: push {r7, lr}
-; CHECK-DARWIN-THUMB: push {r4, r7, lr}
+; CHECK-DARWIN-THUMB: push {r7, lr}