Commit Graph

2 Commits

Author SHA1 Message Date
Peter Collingbourne
dc1a030aec ARM: Align functions containing Thumb-2 jump tables to 4 bytes.
Functions with jump tables need an alignment of 4 because they use the ADR
instruction, which aligns the PC to 4 bytes before adding an offset.

Differential Revision: http://reviews.llvm.org/D9424

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236327 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-01 18:05:59 +00:00
Peter Collingbourne
b28abbf98b ARM: Only enforce 4-byte alignment on Thumb-2 functions with constant pools.
This appears to have been introduced back in r76698 as part of an unrelated
change. I can find no official ARM documentation stating that Thumb-2 functions
require 4-byte alignment; in fact, ARM documentation appears to contradict
this (see, e.g., ARM Architecture Reference Manual Thumb-2 Supplement,
section 2.6.1: "Thumb-2 enforces 16-bit alignment on all instructions.").

Also remove code that sets alignment for ARM functions, which is redundant
with code in the MachineFunction constructor, and remove the hidden
-arm-align-constant-islands flag, which has been enabled by default since
r146739 (Dec 2011) and has probably received sufficient testing by now.

Differential Revision: http://reviews.llvm.org/D9138

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235636 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-23 20:31:22 +00:00