[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop...
authorOrlando Cazalet-Hyams <orlando.hyams@sony.com>
Wed, 19 Jun 2019 10:50:47 +0000 (10:50 +0000)
committerOrlando Cazalet-Hyams <orlando.hyams@sony.com>
Wed, 19 Jun 2019 10:50:47 +0000 (10:50 +0000)
commit1251cac62af531401f3012e1975a973ac5c7e3b1
tree3c40dae7d9c73a3d71dd9d5b6e14a4c2b469c3bc
parent45d19fb470616851a1e2b15f247739c60902445c
[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion

Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here:

A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins.
B) Instructions in the middle block have different line numbers which give the impression of another iteration.

In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks.

I have set up a separate review D61933 for a fix which is required for this patch.

Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel, jmorse

Reviewed By: hfinkel, jmorse

Subscribers: jmorse, javed.absar, eraman, kcc, bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D60831

> llvm-svn: 363046

llvm-svn: 363786
14 files changed:
llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
llvm/test/DebugInfo/AArch64/inlined-argument.ll
llvm/test/Transforms/LoopIdiom/bcmp-debugify-remarks.ll
llvm/test/Transforms/LoopIdiom/memset-debugify-remarks.ll
llvm/test/Transforms/LoopSimplify/dbg-loc.ll
llvm/test/Transforms/LoopSimplify/do-preheader-dbg.ll [new file with mode: 0755]
llvm/test/Transforms/LoopSimplify/for-preheader-dbg.ll [new file with mode: 0755]
llvm/test/Transforms/LoopUnroll/runtime-loop1.ll
llvm/test/Transforms/LoopVectorize/X86/vectorization-remarks-missed.ll
llvm/test/Transforms/LoopVectorize/X86/vectorization-remarks-profitable.ll
llvm/test/Transforms/LoopVectorize/debugloc.ll
llvm/test/Transforms/LoopVectorize/fix-reduction-dbg.ll [new file with mode: 0755]
llvm/test/Transforms/LoopVectorize/unsafe-dep-remark.ll