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| author | Richard Biener <rguenther@suse.de> | 2020-04-16 09:37:44 +0200 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2020-04-16 12:54:38 +0200 |
| commit | eafeba3e5187a53a4c08a3285b4b220e1ab68b60 (patch) | |
| tree | 130e5753d2a1ad6a56f8c33c1c51c2f13e5e7a2d /gcc | |
| parent | 437eea66a4b010d8e94aa81c2b40ccf0588e5fab (diff) | |
| download | gcc-eafeba3e5187a53a4c08a3285b4b220e1ab68b60.zip gcc-eafeba3e5187a53a4c08a3285b4b220e1ab68b60.tar.gz gcc-eafeba3e5187a53a4c08a3285b4b220e1ab68b60.tar.bz2 | |
middle-end/94614 - avoid multiword moves to nothing
This adjusts emit_move_multi_word to handle moves into paradoxical
subregs parts that are not there and adjusts lower-subregs
CLOBBER resolving to deal with those as well.
2020-04-16 Richard Biener <rguenther@suse.de>
PR middle-end/94614
* expr.c (emit_move_multi_word): Do not generate code when
the destination part is undefined_operand_subword_p.
* lower-subreg.c (resolve_clobber): Look through a paradoxica
subreg.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 8 | ||||
| -rw-r--r-- | gcc/expr.c | 5 | ||||
| -rw-r--r-- | gcc/lower-subreg.c | 4 |
3 files changed, 17 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 5fef2d2..9f2f5db 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2020-04-16 Richard Biener <rguenther@suse.de> + + PR middle-end/94614 + * expr.c (emit_move_multi_word): Do not generate code when + the destination part is undefined_operand_subword_p. + * lower-subreg.c (resolve_clobber): Look through a paradoxica + subreg. + 2020-04-16 Martin Jambor <mjambor@suse.cz> PR tree-optimization/94598 @@ -3692,6 +3692,11 @@ emit_move_multi_word (machine_mode mode, rtx x, rtx y) need_clobber = false; for (i = 0; i < CEIL (mode_size, UNITS_PER_WORD); i++) { + /* Do not generate code for a move if it would go entirely + to the non-existing bits of a paradoxical subreg. */ + if (undefined_operand_subword_p (x, i)) + continue; + rtx xpart = operand_subword (x, i, 1, mode); rtx ypart; diff --git a/gcc/lower-subreg.c b/gcc/lower-subreg.c index a170f0f..a11e535 100644 --- a/gcc/lower-subreg.c +++ b/gcc/lower-subreg.c @@ -1150,6 +1150,10 @@ resolve_clobber (rtx pat, rtx_insn *insn) int ret; reg = XEXP (pat, 0); + /* For clobbers we can look through paradoxical subregs which + we do not handle in simplify_gen_subreg_concatn. */ + if (paradoxical_subreg_p (reg)) + reg = SUBREG_REG (reg); if (!resolve_reg_p (reg) && !resolve_subreg_p (reg)) return false; |