mirror of
https://github.com/gcc-mirror/gcc.git
synced 2026-05-06 14:59:39 +02:00
b2fc711494
In the PR code we have the somewhat rare case that we need to reload a vector subreg of a scalar register, (subreg:V2HI (reg:DI)). What complicates things is that the test is compiled with -mrvv-vector-bits=zvl, so VLS-only mode. Unfortunately, we can still get VLA-named modes that are actually VLS modes (i.e. that have a constant number of units). For moving real VLS modes we simply use (define_insn_and_split "*mov<mode>" [(set (match_operand:VLS_AVL_IMM 0 "reg_or_mem_operand" "=vr, m, vr") (match_operand:VLS_AVL_IMM 1 "reg_or_mem_operand" " m,vr, vr"))] Here, lra recognizes cycle danger, quickly switches to the memory alternative and the resulting code is as expected - we perform a vector load from that memory the DImode reg was spilled to. For VLA (named) modes the mov insn is (define_insn_and_split "*mov<V_FRACT:mode><P:mode>_lra" [(set (match_operand:V_FRACT 0 "reg_or_mem_operand" "=vr, m,vr") (match_operand:V_FRACT 1 "reg_or_mem_operand" " m,vr,vr")) (clobber (match_scratch:P 2 "=&r,&r,X"))] The extra clobber here is an optimization: For modes smaller than a full register we want to store the actual size, rather than always the full vector size. If that mode size happens to exceed 32, instead of using an immediate we need to move it to a register so vsetvl can consume it. As the second mov insn above has three operands lra never checks for cycle danger and promptly creates a cycle :) This patch loosens the conditions on the cycle check by allowing a third operand that is a clobber. PR rtl-optimization/123381 gcc/ChangeLog: * lra-constraints.cc (process_alt_operands): Detect cycles in three-operand moves with clobber. (curr_insn_transform): Don't write back a scratch operand. gcc/testsuite/ChangeLog: * gcc.target/riscv/rvv/autovec/pr123381.c: New test.
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.