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nv50/ir: flip shl(add, imm) into add(shl, imm) 

This works when the add also has an immediate. This often happens in
address calculations. These addresses can then be inlined as well.

On code targeted to SM35:

total instructions in shared programs : 6223346 -> 6206257 (-0.27%)
total gprs used in shared programs    : 911075 -> 911045 (-0.00%)
total local used in shared programs   : 39072 -> 39072 (0.00%)

                local        gpr       inst      bytes
    helped           0         119        3664        3664
      hurt           0          74          15          15

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
This commit is contained in:
Ilia Mirkin 2015-12-04 16:05:56 -05:00
parent a4eff86f4a
commit 31fde8faba
1 changed files with 34 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
View File

@ -1132,13 +1132,43 @@ ConstantFolding::opnd(Instruction *i, ImmediateValue &imm0, int s)
break;
// try to concatenate shifts
Instruction *si = i->getSrc(0)->getInsn();
if (!si || si->op != OP_SHL)
if (!si)
break;
ImmediateValue imm1;
if (si->src(1).getImmediate(imm1)) {
switch (si->op) {
case OP_SHL:
if (si->src(1).getImmediate(imm1)) {
bld.setPosition(i, false);
i->setSrc(0, si->getSrc(0));
i->setSrc(1, bld.loadImm(NULL, imm0.reg.data.u32 + imm1.reg.data.u32));
}
break;
case OP_SUB:
case OP_ADD:
int adds;
if (isFloatType(si->dType))
return;
if (si->op != OP_SUB && si->src(0).getImmediate(imm1))
adds = 0;
else if (si->src(1).getImmediate(imm1))
adds = 1;
else
return;
// SHL(ADD(x, y), z) = ADD(SHL(x, z), SHL(y, z))
// This is more operations, but if one of x, y is an immediate, then
// we can get a situation where (a) we can use ISCADD, or (b)
// propagate the add bit into an indirect load.
bld.setPosition(i, false);
i->setSrc(0, si->getSrc(0));
i->setSrc(1, bld.loadImm(NULL, imm0.reg.data.u32 + imm1.reg.data.u32));
i->op = si->op;
i->setSrc(adds, bld.loadImm(NULL, imm1.reg.data.u32 << imm0.reg.data.u32));
i->setSrc(!adds, bld.mkOp2v(OP_SHL, i->dType,
bld.getSSA(i->def(0).getSize(), i->def(0).getFile()),
si->getSrc(!adds),
bld.mkImm(imm0.reg.data.u32)));
break;
default:
return;
}
}
break;