https://llvm.org/bugs/show_bug.cgi?id=30798
Bug ID: 30798
Summary: VirtRegRewriter fails to set properties on BUNDLE
instructions
Product: libraries
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: normal
Priority: P
Component: Register Allocator
Assignee: unassignedb...@nondot.org
Reporter: mattias.v.eriks...@ericsson.com
CC: llvm-bugs@lists.llvm.org
Classification: Unclassified
In my out-of-tree back-end we run the register allocator after
bundling of instructions. The register allocator handles this mostly
fine, but I think there is a bug related to imp-use on subregister
definitions:
# *** IR Dump Before Virtual Register Rewriter ***:
BUNDLE %vreg1<imp-def>
* %vreg1:hiAcc<def> = ...
%vreg1 is a register pair which consists of hiAcc and loAcc. It is
allocated %a32, in which %a3 is hiAcc. After register allocation
imp-use is added on the bundled instruction but not on the BUNDLE
head.
# *** IR Dump After Virtual Register Rewriter ***:
BUNDLE %a32<imp-def>
* %a3<def> = ... %a32<imp-use>
I think %a32<imp-use> should be added to the BUNDLE head:
BUNDLE %a32<imp-def>, %a32<imp-use>
* %a3<def> = ... %a32<imp-use>
The relevant code is in VirtRegRewriter::rewrite():
// Add any missing super-register kills after rewriting the whole
// instruction.
while (!SuperKills.empty())
MI->addRegisterKilled(SuperKills.pop_back_val(), TRI, true);
while (!SuperDeads.empty())
MI->addRegisterDead(SuperDeads.pop_back_val(), TRI, true);
while (!SuperDefs.empty())
MI->addRegisterDefined(SuperDefs.pop_back_val(), TRI);
Should this be updated to also add the relevant flags on the bundle
head?
--
You are receiving this mail because:
You are on the CC list for the bug.
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
