Commit Graph

4 Commits

Author SHA1 Message Date
Andrew Kaylor a11d020699 Revert r295004 (Add MXCSR) due to errors reported by MachineVerifier
I am leaving the code in clang which filters mxcsr from the clobber list because that is still technically correct and will be useful again when the MXCSR register is reintroduced.

llvm-svn: 297664
2017-03-13 20:35:10 +00:00
Andrew Kaylor 709f1c2a9b [X86] Add MXCSR register
This adds MXCSR to the set of recognized registers for X86 targets and updates the instructions that read or write it. I do not intend for all of the various floating point instructions that implicitly use the control bits or update the status bits of this register to ever have that usage modeled by default. However, when constrained floating point modes (such as strict FP exception status modeling or dynamic rounding modes) are enabled, implicit use/def information for MXCSR will be added to those instructions.

Until those additional updates are made this should cause (almost?) no functional changes. Theoretically, this will prevent instructions like LDMXCSR and STMXCSR from being moved past one another, but that should be prevented anyway and I haven't found a case where it is happening now.

Differential Revision: https://reviews.llvm.org/D29903

llvm-svn: 295004
2017-02-13 23:38:52 +00:00
Chad Rosier 4f0dad1674 [IPRA] Properly compute register usage at call sites.
Differential Revision: http://reviews.llvm.org/D21395
Patch by Vivek Pandya.
PR28144

llvm-svn: 275087
2016-07-11 18:45:49 +00:00
Mehdi Amini bbacddfe92 Interprocedural Register Allocation (IPRA) Analysis
Add an option to enable the analysis of MachineFunction register
usage to extract the list of clobbered registers.

When enabled, the CodeGen order is changed to be bottom up on the Call
Graph.

The analysis is split in two parts, RegUsageInfoCollector is the
MachineFunction Pass that runs post-RA and collect the list of
clobbered registers to produce a register mask.

An immutable pass, RegisterUsageInfo, stores the RegMask produced by
RegUsageInfoCollector, and keep them available. A future tranformation
pass will use this information to update every call-sites after
instruction selection.

Patch by Vivek Pandya <vivekvpandya@gmail.com>

Differential Revision: http://reviews.llvm.org/D20769

llvm-svn: 272403
2016-06-10 16:19:46 +00:00