search for: d2214

...be very far from each other. This makes stack traces misleading and very hard to reason about. Mostly, we are running in this issue with sanitizers, where we care about performance (and therefore don't use -O0), but want stacktraces to be mostly sane anyway. http://llvm-reviews.chandlerc.com/D2214 http://llvm-reviews.chandlerc.com/D2215 I've prepared two patches that deal with these issues by disabling this and similar optimizations when building with sanitizers. Would it be reasonable to disable these optimizations at -O1 instead?

Reid, by the other CFG simplification, do you mean this case in http://llvm-reviews.chandlerc.com/D2214? 1: if (x < 0) 2: if (y < 0) 3: do_something(); Yes, this is only bad for MSan (and probably for sampling-based PGO, but that's a whole different story). But the current version of D2214 disables this optimization at SimplifyUncondBranch() point, which also covers HoistThenElseCod...

On 26 November 2013 16:59, Reid Kleckner <rnk at google.com> wrote: > I'd support disabling tail merging of calls at -O1. The other CFG > simplification doesn't seem like that big of a deal though for general > debugging, though. > So, do we have two ways of running SimplifyCFG? One for O1 and one for O2+, and selectively disabling parts of it? --renato --------------

...s makes stack traces misleading and very hard to reason > about. > > Mostly, we are running in this issue with sanitizers, where we care > about performance (and therefore don't use -O0), but want stacktraces > to be mostly sane anyway. > > http://llvm-reviews.chandlerc.com/D2214 > http://llvm-reviews.chandlerc.com/D2215 > > I've prepared two patches that deal with these issues by disabling > this and similar optimizations when building with sanitizers. > > Would it be reasonable to disable these optimizations at -O1 instead? > _____________________...

...abel %if.end3 >>>> where all 3 instructions are associated with line 1. >>>> >>>> This patch disables folding of conditional branches in functions with >>>> sanitize_memory attribute. >>>> >>>> http://llvm-reviews.chandlerc.com/D2214 >>>> >>>> Files: >>>> lib/Transforms/Utils/SimplifyCFG.cpp >>>> test/Transforms/SimplifyCFG/branch-fold-msan.ll >>>> >>>> Index: lib/Transforms/Utils/SimplifyCFG.cpp >>>> ========================================...

...t;>> where all 3 instructions are associated with line 1. >>>>> >>>>> This patch disables folding of conditional branches in functions with >>>>> sanitize_memory attribute. >>>>> >>>>> http://llvm-reviews.chandlerc.com/D2214 >>>>> >>>>> Files: >>>>> lib/Transforms/Utils/SimplifyCFG.cpp >>>>> test/Transforms/SimplifyCFG/branch-fold-msan.ll >>>>> >>>>> Index: lib/Transforms/Utils/SimplifyCFG.cpp >>>>> ============...

...3 instructions are associated with line 1. >>>>>> >>>>>> This patch disables folding of conditional branches in functions with >>>>>> sanitize_memory attribute. >>>>>> >>>>>> http://llvm-reviews.chandlerc.com/D2214 >>>>>> >>>>>> Files: >>>>>> lib/Transforms/Utils/SimplifyCFG.cpp >>>>>> test/Transforms/SimplifyCFG/branch-fold-msan.ll >>>>>> >>>>>> Index: lib/Transforms/Utils/SimplifyCFG.cpp >>&...

...s makes stack traces misleading and very hard to reason > about. > > Mostly, we are running in this issue with sanitizers, where we care > about performance (and therefore don't use -O0), but want stacktraces > to be mostly sane anyway. > > http://llvm-reviews.chandlerc.com/D2214 > http://llvm-reviews.chandlerc.com/D2215 > > I've prepared two patches that deal with these issues by disabling > this and similar optimizations when building with sanitizers. > > Would it be reasonable to disable these optimizations at -O1 instead? This is a bit of a tangent...

...3 instructions are associated with line 1. >>>>>> >>>>>> This patch disables folding of conditional branches in functions with >>>>>> sanitize_memory attribute. >>>>>> >>>>>> http://llvm-reviews.chandlerc.com/D2214 >>>>>> >>>>>> Files: >>>>>> lib/Transforms/Utils/SimplifyCFG.cpp >>>>>> test/Transforms/SimplifyCFG/branch-fold-msan.ll >>>>>> >>>>>> Index: lib/Transforms/Utils/SimplifyCFG.cpp >>&...

...iated with line 1. > >>>>>> > >>>>>> This patch disables folding of conditional branches in functions > >>>>>> with sanitize_memory attribute. > >>>>>> > >>>>>> http://llvm-reviews.chandlerc.com/D2214 > >>>>>> > >>>>>> Files: > >>>>>> lib/Transforms/Utils/SimplifyCFG.cpp > >>>>>> test/Transforms/SimplifyCFG/branch-fold-msan.ll > >>>>>> > >>>>>> Index: lib/Transforms/U...

...; instructions are associated with line 1. >>>>>> >>>>>> This patch disables folding of conditional branches in functions >>>>>> with sanitize_memory attribute. >>>>>> >>>>>> http://llvm-reviews.chandlerc.com/D2214 >>>>>> >>>>>> Files: >>>>>> lib/Transforms/Utils/SimplifyCFG.cpp >>>>>> test/Transforms/SimplifyCFG/branch-fold-msan.ll >>>>>> >>>>>> Index: lib/Transforms/Utils/SimplifyCFG.cpp >>&...

...t; instructions are associated with line 1. >>>>>> >>>>>> This patch disables folding of conditional branches in functions >>>>>> with sanitize_memory attribute. >>>>>> >>>>>> http://llvm-reviews.chandlerc.com/D2214 >>>>>> >>>>>> Files: >>>>>> lib/Transforms/Utils/SimplifyCFG.cpp >>>>>> test/Transforms/SimplifyCFG/branch-fold-msan.ll >>>>>> >>>>>> Index: lib/Transforms/Utils/SimplifyCFG.cpp >>&...

...gt; >>>>>> This patch disables folding of conditional branches in > > >>>>>> functions > > >>>>>> with sanitize_memory attribute. > > >>>>>> > > >>>>>> http://llvm-reviews.chandlerc.com/D2214 > > >>>>>> > > >>>>>> Files: > > >>>>>> lib/Transforms/Utils/SimplifyCFG.cpp > > >>>>>> test/Transforms/SimplifyCFG/branch-fold-msan.ll > > >>>>>> > > >>>>>&g...

...>>>> > >>>>>> This patch disables folding of conditional branches in > >>>>>> functions > >>>>>> with sanitize_memory attribute. > >>>>>> > >>>>>> http://llvm-reviews.chandlerc.com/D2214 > >>>>>> > >>>>>> Files: > >>>>>> lib/Transforms/Utils/SimplifyCFG.cpp > >>>>>> test/Transforms/SimplifyCFG/branch-fold-msan.ll > >>>>>> > >>>>>> Index: lib/Transforms/Uti...

...t; >>>>>> This patch disables folding of conditional branches in > > >>>>>> functions > > >>>>>> with sanitize_memory attribute. > > >>>>>> > > >>>>>> http://llvm-reviews.chandlerc.com/D2214 > > >>>>>> > > >>>>>> Files: > > >>>>>> lib/Transforms/Utils/SimplifyCFG.cpp > > >>>>>> test/Transforms/SimplifyCFG/branch-fold-msan.ll > > >>>>>> > > >>>>>...

...iated with line 1. > >>>>>> > >>>>>> This patch disables folding of conditional branches in functions > >>>>>> with sanitize_memory attribute. > >>>>>> > >>>>>> http://llvm-reviews.chandlerc.com/D2214 > >>>>>> > >>>>>> Files: > >>>>>> lib/Transforms/Utils/SimplifyCFG.cpp > >>>>>> test/Transforms/SimplifyCFG/branch-fold-msan.ll > >>>>>> > >>>>>> Index: lib/Transforms/U...