4 Commits

Author	SHA1	Message	Date
Tim Northover	a603c4076c	ARM: recommit r237590: allow jump tables to be placed as constant islands. ... The original version didn't properly account for the base register being modified before the final jump, so caused miscompilations in Chromium and LLVM. I've fixed this and tested with an LLVM self-host (I don't have the means to build & test Chromium). The general idea remains the same: in pathological cases jump tables can be too far away from the instructions referencing them (like other constants) so they need to be movable. Should fix PR23627. llvm-svn: 238680	2015-05-31 19:22:07 +00:00
Peter Collingbourne	7e814d100b	Revert r237590, "ARM: allow jump tables to be placed as constant islands." ... Caused a miscompile of the Android port of Chromium, details forthcoming. llvm-svn: 237972	2015-05-21 23:20:55 +00:00
Tim Northover	12c41af07c	ARM: allow jump tables to be placed as constant islands. ... Previously, they were forced to immediately follow the actual branch instruction. This was usually OK (the LEAs actually accessing them got emitted nearby, and weren't usually separated much afterwards). Unfortunately, a sufficiently nasty phi elimination dumps many instructions right before the basic block terminator, and this can increase the range too much. This patch frees them up to be placed as usual by the constant islands pass, and consequently has to slightly modify the form of TBB/TBH tables to refer to a PC-relative label at the final jump. The other jump table formats were already position-independent. rdar://20813304 llvm-svn: 237590	2015-05-18 17:10:40 +00:00
Chad Rosier	620fb2206d	[ARMConstantIsland] Insert tbb/tbh optimization where previous jump table resided. ... llvm-svn: 224165	2014-12-12 23:27:40 +00:00