RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-23 03:02:36 +01:00
Code Issues Projects Releases Wiki Activity

AMDGPU: Fix AMDGPUUnifyDivergentExitNodes with no normal returns

Browse Source 
Summary:
The code was assuming in a few places that if there was only one exit
from the function that it was a normal return, which is invalid. It
could be an infinite loop, in which case we still need to insert the
usual fake edge so that the null export happens. This fixes shaders that
end with an infinite loop that discards.

Reviewers: arsenm, nhaehnle, critson

Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, t-tye, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71192
This commit is contained in:
Connor Abbott 2019-12-09 12:04:00 +01:00
parent b3f994414f
commit f758df6c01
2 changed files with 17 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
lib/Target/AMDGPU/AMDGPUUnifyDivergentExitNodes.cpp
View File

@ -195,8 +195,6 @@ static BasicBlock *unifyReturnBlockSet(Function &F,
bool AMDGPUUnifyDivergentExitNodes::runOnFunction(Function &F) {
auto &PDT = getAnalysis<PostDominatorTreeWrapperPass>().getPostDomTree();
if (PDT.getRoots().size() <= 1)
return false;
LegacyDivergenceAnalysis &DA = getAnalysis<LegacyDivergenceAnalysis>();
@ -321,7 +319,7 @@ bool AMDGPUUnifyDivergentExitNodes::runOnFunction(Function &F) {
if (ReturningBlocks.empty())
return false; // No blocks return
if (ReturningBlocks.size() == 1)
if (ReturningBlocks.size() == 1 && !InsertExport)
return false; // Already has a single return block
const TargetTransformInfo &TTI

16
test/CodeGen/AMDGPU/kill-infinite-loop.ll
View File

@ -45,6 +45,22 @@ end:
ret void
}
; test the case where there's only a kill in an infinite loop
; CHECK-LABEL: only_kill
; CHECK: exp null off, off, off, off done vm
; CHECK-NEXT: s_endpgm
; SIInsertSkips inserts an extra null export here, but it should be harmless.
; CHECK: exp null off, off, off, off done vm
; CHECK-NEXT: s_endpgm
define amdgpu_ps void @only_kill() #0 {
main_body:
br label %loop
loop:
call void @llvm.amdgcn.kill(i1 false) #3
br label %loop
}
; In case there's an epilog, we shouldn't have to do this.
; CHECK-LABEL: return_nonvoid
; CHECK-NOT: exp null off, off, off, off done vm