Commit Graph

14 Commits

Author SHA1 Message Date
Sanjay Patel 7552d0d2e6 [InstCombine] do not shrink switch conditions to illegal types (PR29009)
This patch makes shrinking switch conditions less aggressive which was introduced by:
rL274233

Note that we have 2 new bugs to track potential follow-ups that might have solved PR29009
in different ways:
https://bugs.llvm.org/show_bug.cgi?id=39569
https://bugs.llvm.org/show_bug.cgi?id=39578

Patch by:
@dendibakh (Denis Bakhvalov)

Differential Revision: https://reviews.llvm.org/D54115

llvm-svn: 346315
2018-11-07 14:12:41 +00:00
Peter Collingbourne 10c500ddc0 opt: Rename -default-data-layout flag to -data-layout and make it always override the layout.
There isn't much point in a flag that only works if the data layout is empty.

Differential Revision: https://reviews.llvm.org/D30014

llvm-svn: 295468
2017-02-17 17:36:52 +00:00
Gerolf Hoflehner 22921338b1 [InstCombine] Added regression test to narrow-swich.ll
llvm-svn: 293018
2017-01-25 04:34:59 +00:00
Sanjay Patel 052220c5c8 remove stale FIXME note from test; NFC
llvm-svn: 289445
2016-12-12 16:20:21 +00:00
Sanjay Patel e730ce87a5 [InstCombine] fix bug when offsetting case values of a switch (PR31260)
We could truncate the condition and then try to fold the add into the
original condition value causing wrong case constants to be used.

Move the offset transform ahead of the truncate transform and return
after each transform, so there's no chance of getting confused values.

Fix for:
https://llvm.org/bugs/show_bug.cgi?id=31260

llvm-svn: 289442
2016-12-12 16:13:52 +00:00
Sanjay Patel 2b060c7700 [InstCombine] add test to show PR31260 miscompile; NFC
llvm-svn: 289437
2016-12-12 15:28:44 +00:00
Sanjay Patel 7c6eab5777 [InstCombine] shrink switch conditions better (PR24766)
https://llvm.org/bugs/show_bug.cgi?id=24766#c2

This removes a hack that was added for the benefit of x86 codegen. 
It prevented shrinking the switch condition even to smaller legal (DataLayout) types.
We have a safety mechanism in CGP after:
http://reviews.llvm.org/rL251857
...so we're free to use the optimal (smallest) IR type now.

Differential Revision: http://reviews.llvm.org/D12965

llvm-svn: 274233
2016-06-30 14:51:21 +00:00
Sanjay Patel 23fa090738 regenerate checks and add a run to show missed shrinkage
llvm-svn: 269449
2016-05-13 18:04:39 +00:00
Bruno Cardoso Lopes f6cf8ad4e5 Reapply: [InstCombine] Fix visitSwitchInst to use right operand types for sub cstexpr
The visitSwitchInst generates SUB constant expressions to recompute the
switch condition. When truncating the condition to a smaller type, SUB
expressions should use the previous type (before trunc) for both
operands. Also, fix code to also return the modified switch when only
the truncation is performed.

This fixes an assertion crash.

Differential Revision: http://reviews.llvm.org/D6644

rdar://problem/19191835

llvm-svn: 224588
2014-12-19 17:12:35 +00:00
Bruno Cardoso Lopes 3be15b2fa6 Revert "[InstCombine] Fix visitSwitchInst to use right operand types for sub cstexpr"
Reverts commit r224574 to appease buildbots:

The visitSwitchInst generates SUB constant expressions to recompute the
switch condition. When truncating the condition to a smaller type, SUB
expressions should use the previous type (before trunc) for both
operands. This fixes an assertion crash.

llvm-svn: 224576
2014-12-19 14:36:24 +00:00
Bruno Cardoso Lopes c9005f2f2b [InstCombine] Fix visitSwitchInst to use right operand types for sub cstexpr
The visitSwitchInst generates SUB constant expressions to recompute the
switch condition. When truncating the condition to a smaller type, SUB
expressions should use the previous type (before trunc) for both
operands. This fixes an assertion crash.

Differential Revision: http://reviews.llvm.org/D6644

rdar://problem/19191835

llvm-svn: 224574
2014-12-19 14:23:15 +00:00
Akira Hatanaka 5c221ef98f Reapply r219832 - InstCombine: Narrow switch instructions using known bits.
The code committed in r219832 asserted when it attempted to shrink a switch
statement whose type was larger than 64-bit.

llvm-svn: 219902
2014-10-16 06:00:46 +00:00
Akira Hatanaka 40c2cf4afc Revert r219832.
llvm-svn: 219884
2014-10-16 01:17:02 +00:00
Akira Hatanaka 5bb9346a45 InstCombine: Narrow switch instructions using known bits.
Truncate the operands of a switch instruction to a narrower type if the upper
bits are known to be all ones or zeros.

rdar://problem/17720004

llvm-svn: 219832
2014-10-15 19:05:50 +00:00