From b35ad6e7016a877def4b3d2d22b3a2265a68e2eb Mon Sep 17 00:00:00 2001 From: Rob Clark Date: Thu, 7 Apr 2016 12:53:07 -0400 Subject: freedreno/ir3: cleanup double cmps.s from frontend Since we cannot mov into a predicate register, the frontend uses a 'cmps.s p0.x, cond, 0' as a stand-in for mov to p0.x. It does this since it has no way to know that the source cond instruction (ie. for a kill, br, etc) will only be used to write the predicate reg. Detect this, and re-write the instruction writing p0.x to skip the original cmps.[sfu]. (It is done like this, rather than re-writing the dest of the first cmps.[sfu] in case the first cmps.[sfu] actually has other users.) Signed-off-by: Rob Clark --- src/gallium/drivers/freedreno/ir3/ir3_cp.c | 31 ++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/src/gallium/drivers/freedreno/ir3/ir3_cp.c b/src/gallium/drivers/freedreno/ir3/ir3_cp.c index 6037becf22f..e8a2f099391 100644 --- a/src/gallium/drivers/freedreno/ir3/ir3_cp.c +++ b/src/gallium/drivers/freedreno/ir3/ir3_cp.c @@ -442,6 +442,37 @@ instr_cp(struct ir3_instruction *instr) instr_cp(instr->address); ir3_instr_set_address(instr, eliminate_output_mov(instr->address)); } + + /* we can end up with extra cmps.s from frontend, which uses a + * + * cmps.s p0.x, cond, 0 + * + * as a way to mov into the predicate register. But frequently 'cond' + * is itself a cmps.s/cmps.f/cmps.u. So detect this special case and + * just re-write the instruction writing predicate register to get rid + * of the double cmps. + */ + if ((instr->opc == OPC_CMPS_S) && + (instr->regs[0]->num == regid(REG_P0, 0)) && + ssa(instr->regs[1]) && + (instr->regs[2]->flags & IR3_REG_IMMED) && + (instr->regs[2]->iim_val == 0)) { + struct ir3_instruction *cond = ssa(instr->regs[1]); + switch (cond->opc) { + case OPC_CMPS_S: + case OPC_CMPS_F: + case OPC_CMPS_U: + instr->opc = cond->opc; + instr->flags = cond->flags; + instr->cat2 = cond->cat2; + instr->address = cond->address; + instr->regs[1] = cond->regs[1]; + instr->regs[2] = cond->regs[2]; + break; + default: + break; + } + } } void -- cgit v1.2.3