Commit Graph

6 Commits

Author SHA1 Message Date
Sanjay Patel 5a48aef3f0 [x86, MemCmpExpansion] allow 2 pairs of loads per block (PR33325)
This is the last step needed to fix PR33325:
https://bugs.llvm.org/show_bug.cgi?id=33325

We're trading branch and compares for loads and logic ops. 
This makes the code smaller and hopefully faster in most cases.

The 24-byte test shows an interesting construct: we load the trailing scalar 
elements into vector registers and generate the same pcmpeq+movmsk code that 
we expected for a pair of full vector elements (see the 32- and 64-byte tests).

Differential Revision: https://reviews.llvm.org/D41714

llvm-svn: 321934
2018-01-06 16:16:04 +00:00
Sanjay Patel f344987cad [ExpandMemcmp] rename variables and add hook to override pref for number of loads per block; NFC
The preference only applies to 'memcmp() == 0' expansion, so try to make that clearer.
x86 will likely benefit by increasing the default value from '1' to '2' as seen in PR33325:
https://bugs.llvm.org/show_bug.cgi?id=33325
...so that is the planned follow-up to this clean-up step.

llvm-svn: 321756
2018-01-03 20:02:39 +00:00
Clement Courbet 6f42de3062 [NFC][CodeGen][ExpandMemCmp] Fix documentation.
llvm-svn: 320960
2017-12-18 07:32:48 +00:00
Michael Zolotukhin c468b648fd Remove redundant includes from lib/CodeGen.
llvm-svn: 320619
2017-12-13 21:30:47 +00:00
David Blaikie b3bde2ea50 Fix a bunch more layering of CodeGen headers that are in Target
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).

llvm-svn: 318490
2017-11-17 01:07:10 +00:00
Clement Courbet 063bed9baf re-land [ExpandMemCmp] Split ExpandMemCmp from CodeGen into its own pass."
Fix undefined references: ExpandMemCmp belongs to CodeGen/, not Scalar/.

llvm-svn: 317318
2017-11-03 12:12:27 +00:00