RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-12-11 13:37:07 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

[AMDGPU] Disable nested endcf collapse

Browse Source 
The assumption is that conditional regions are perfectly nested
and a mask restored at the exit from the inner block will be
completely covered by a mask restored in the outer.

It turns out with our current structurizer this is not always
the case.

Disable the optimization for now, but I want to keep it around
for a while to either try after further structurizer changes or
to move it into control flow lowering where we have more info
and reuse the test.

Differential Revision: https://reviews.llvm.org/D75958
This commit is contained in:
Stanislav Mekhanoshin 2020-03-10 13:29:11 -07:00
parent 58f4a73f70
commit fcfb1332a7
3 changed files with 12 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
lib/Target/AMDGPU/SIOptimizeExecMaskingPreRA.cpp
View File

@ -31,6 +31,10 @@ using namespace llvm;
#define DEBUG_TYPE "si-optimize-exec-masking-pre-ra"
static cl::opt<bool>
RemoveRedundantEndcf("amdgpu-remove-redundant-endcf",
cl::init(false), cl::ReallyHidden);
namespace {
class SIOptimizeExecMaskingPreRA : public MachineFunctionPass {
@ -379,7 +383,13 @@ bool SIOptimizeExecMaskingPreRA::runOnMachineFunction(MachineFunction &MF) {
continue;
}
if (!RemoveRedundantEndcf)
continue;
// Try to collapse adjacent endifs.
// The assumption is that conditional regions are perfectly nested and
// a mask restored at the exit from the inner block will be completely
// covered by a mask restored in the outer.
auto E = MBB.end();
auto Lead = skipDebugInstructionsForward(MBB.begin(), E);
if (MBB.succ_size() != 1 || Lead == E || !isEndCF(*Lead, TRI, ST))

2
test/CodeGen/AMDGPU/collapse-endcf.ll
View File

@ -1,4 +1,4 @@
; RUN: llc -march=amdgcn -mcpu=tahiti -verify-machineinstrs < %s | FileCheck -enable-var-scope -check-prefixes=GCN,ALL %s
; RUN: llc -march=amdgcn -mcpu=tahiti -verify-machineinstrs -amdgpu-remove-redundant-endcf < %s | FileCheck -enable-var-scope -check-prefixes=GCN,ALL %s
; RUN: llc -march=amdgcn -mcpu=tahiti -verify-machineinstrs -amdgpu-opt-exec-mask-pre-ra=0 < %s | FileCheck -enable-var-scope -check-prefixes=DISABLED,ALL %s
; ALL-LABEL: {{^}}simple_nested_if:

2
test/CodeGen/AMDGPU/collapse-endcf.mir
View File

@ -1,5 +1,5 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -march=amdgcn -verify-machineinstrs -run-pass=si-optimize-exec-masking-pre-ra %s -o - | FileCheck -check-prefix=GCN %s
# RUN: llc -march=amdgcn -verify-machineinstrs -run-pass=si-optimize-exec-masking-pre-ra -amdgpu-remove-redundant-endcf %s -o - | FileCheck -check-prefix=GCN %s
# Make sure dbg_value doesn't change codeegn when collapsing end_cf
---