diff options
| author | Eric Anholt <[email protected]> | 2016-10-05 09:21:37 -0700 |
|---|---|---|
| committer | Eric Anholt <[email protected]> | 2016-10-06 18:09:24 -0700 |
| commit | 7c7bcbbc7dc7b71e1e3bab69fbcbc8fcbe797cbc (patch) | |
| tree | 14b46448f4e18718e54501c1d28ff9085a24088e /src/gallium | |
| parent | d4ae5ca823227214dd1f536e5f4058bede20b2dd (diff) | |
vc4: Drop destination register when it's unused.
This slightly reduces instructions on shader-db, but I think it's just
perturbing register allocation -- the allocator should have always
trivially colored these nodes, before. This commit is just to make QIR
code failing more intelligible when register allocation fails.
Diffstat (limited to 'src/gallium')
| -rw-r--r-- | src/gallium/drivers/vc4/vc4_opt_dead_code.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/src/gallium/drivers/vc4/vc4_opt_dead_code.c b/src/gallium/drivers/vc4/vc4_opt_dead_code.c index f516d388429..1838c394ff9 100644 --- a/src/gallium/drivers/vc4/vc4_opt_dead_code.c +++ b/src/gallium/drivers/vc4/vc4_opt_dead_code.c @@ -102,9 +102,30 @@ qir_opt_dead_code(struct vc4_compile *c) continue; } + if (qir_has_side_effects(c, inst)) + continue; + if (inst->sf || - qir_has_side_effects(c, inst) || has_nonremovable_reads(c, inst)) { + /* If we can't remove the instruction, but we + * don't need its destination value, just + * remove the destination. The register + * allocator would trivially color it and it + * wouldn't cause any register pressure, but + * it's nicer to read the QIR code without + * unused destination regs. + */ + if (inst->dst.file == QFILE_TEMP) { + if (debug) { + fprintf(stderr, + "Removing dst from: "); + qir_dump_inst(c, inst); + fprintf(stderr, "\n"); + } + c->defs[inst->dst.index] = NULL; + inst->dst.file = QFILE_NULL; + progress = true; + } continue; } |