[Bug c++/119120] New: Unnecessary fld when assigning real or imaginary part of a complex variable

: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: vajdaz at protonmail dot com Target Milestone: --- Following C++ code generates the assembly underneath when compiling with -O0 for x86 architecture (32 bit). C++ source

[Bug target/93934] Unnecessary fld of uninitialized float stack variable results in ub of valid C++ code

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93934 --- Comment #23 from Zoltan Vajda --- (In reply to Uroš Bizjak from comment #20) > (In reply to jos...@codesourcery.com from comment #16) > > I don't think this bug is anything to do with -fsignaling-nans, for the > > same reason as applies to b

[Bug target/93934] Unnecessary fld of uninitialized float stack variable results in ub of valid C++ code

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93934 --- Comment #19 from Zoltan Vajda --- (In reply to Uroš Bizjak from comment #18) > The following patch fixes the PR, see the comment inline: > > --cut here-- > diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c > index 6e

[Bug target/93934] Unnecessary fld of uninitialized float stack variable results in ub of valid C++ code

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93934 --- Comment #15 from Zoltan Vajda --- In my special case, I have an embedded realtime application with a lot of FP atithmetic on Intel 32 bit architecture (huge and complex legacy codebase). FPU exceptions are enabled, so loading an SNaN results

[Bug target/93934] Unnecessary fld of uninitialized float stack variable results in ub of valid C++ code

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93934 --- Comment #12 from Zoltan Vajda --- Using -mfpmath=sse here does not help on a 32 bit platfrom. https://gcc.godbolt.org/z/hs1Ef6aj4 At line 31 the assembly code performs the speculative load.

[Bug target/93934] Unnecessary fld of uninitialized float stack variable results in ub of valid C++ code

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93934 --- Comment #9 from Zoltan Vajda --- As I understand it, it is acknowledged, that this is a bug. However, the issue is in state NEW for a quite long time. The issue is still present in GCC 11.2. Do you see any chances for some progress in this ca

[Bug target/93934] Unnecessary fld of uninitialized float stack variable results in ub of valid C++ code

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93934 Zoltan Vajda changed: What|Removed |Added Status|RESOLVED|UNCONFIRMED Resolution|INVALID

[Bug c++/93934] New: Unnecessary fld of uninitialized float stack variable results in ub of valid C++ code

Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: vajdaz at protonmail dot com Target Milestone: --- Valid C++ code is compiled to assembly that seems to be buggy. Below source code and assembly output of the