mirror of
https://github.com/gcc-mirror/gcc.git
synced 2026-05-06 23:25:24 +02:00
3a7143ed83
The recently added patterns for recovering good code generation of conditional operations on RISC-V with Zicond had a nasty little bug causing this bootstrap failure. The main patterns are fine -- in those cases the czero produces a neutral value. So for example a conditional IOR can use a czero to select between an IOR's operand and zero, then we do an unconditional IOR of the common value and the result of the czero. For AND the neutral value is -1 rather than 0. So we need a different sequence. We emit the AND into a temporary. Then select between the common term and zero. Then IOR the temporary with the selected value. That sequence requires the tense of the selection to be inverted which I failed to do in the split RTL output of the pattern. Those had been tested by inspection only and the tense flip was missed. Doko's bootstrap test with zicond enabled by default was able to trip this problem. Thankfully it was easy to reproduce and bisect and was mostly a matter of waiting for builds to run. I've bootstrapped this on one of my BPIs with B, V and Zicond enabled by default. I'll be pushing it to the trunk momentarily. I never actually compared assembly or debugged the resulting code, it was found purely by inspection once I knew where to look. ie, I don't have a testcase for the testsuite, but this is covered by bootstrapping with Zicond enabled. I'd been somewhat worried about this possibility for a while -- the B, V and Zicond extensions are not well represented by CI systems for bootstrap testing. Given the Pioneer here is still limping along, it's a good test of rv64gc and I've hacked things up so that the BPI will enable B, V and Zicond by default. The baseline run is still in progress (bootstrapping and regression testing on the BPI is up to 30 hours now), but we'll have coverage going forward. Obviously when the K3 systems come out the hope is this cycle time will drop meaningfully. PR target/124048 gcc/ * config/riscv/zicond.md (conditional AND patterns): Fix missed flipping the condition's test in RTL output.
This directory contains the GNU Compiler Collection (GCC). The GNU Compiler Collection is free software. See the files whose names start with COPYING for copying permission. The manuals, and some of the runtime libraries, are under different terms; see the individual source files for details. The directory INSTALL contains copies of the installation information as HTML and plain text. The source of this information is gcc/doc/install.texi. The installation information includes details of what is included in the GCC sources and what files GCC installs. See the file gcc/doc/gcc.texi (together with other files that it includes) for usage and porting information. An online readable version of the manual is in the files gcc/doc/gcc.info*. See http://gcc.gnu.org/bugs/ for how to report bugs usefully. Copyright years on GCC source files may be listed using range notation, e.g., 1987-2012, indicating that every year in the range, inclusive, is a copyrightable year that could otherwise be listed individually.