Module: Mesa
Branch: master
Commit: 3079993727ddfe6b09e1f0ec8f834691fd654b46
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=3079993727ddfe6b09e1f0ec8f834691fd654b46
Author: Ilia Mirkin <imir...@alum.mit.edu>
Date: Fri Nov 10 21:47:59 2017 -0500
nv50/ir: optimize signed integer modulo by pow-of-2
It's common to use signed int modulo in GLSL. As it happens, the GLSL
specs allow the result to be undefined, but that seems fairly
surprising. It's not that much more effort to get it right, at least for
positive modulo operators.
Signed-off-by: Ilia Mirkin <imir...@alum.mit.edu>
---
src/gallium/drivers/nouveau/codegen/nv50_ir.cpp | 8 +-----
.../drivers/nouveau/codegen/nv50_ir_peephole.cpp | 31 +++++++++++++++++++---
2 files changed, 29 insertions(+), 10 deletions(-)
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir.cpp
b/src/gallium/drivers/nouveau/codegen/nv50_ir.cpp
index b96f919073..6f12df70a1 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir.cpp
@@ -423,13 +423,7 @@ ImmediateValue::isNegative() const
bool
ImmediateValue::isPow2() const
{
- switch (reg.type) {
- case TYPE_U8:
- case TYPE_U16:
- case TYPE_U32: return util_is_power_of_two(reg.data.u32);
- default:
- return false;
- }
+ return util_is_power_of_two(reg.data.u32);
}
void
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
index 7e4e193e3d..2448c737e7 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
@@ -1054,6 +1054,7 @@ ConstantFolding::opnd(Instruction *i, ImmediateValue
&imm0, int s)
i->op = OP_ADD;
} else
if (s == 1 && !imm0.isNegative() && imm0.isPow2() &&
+ !isFloatType(i->dType) &&
target->isOpSupported(OP_SHLADD, i->dType)) {
i->op = OP_SHLADD;
imm0.applyLog2();
@@ -1163,10 +1164,34 @@ ConstantFolding::opnd(Instruction *i, ImmediateValue
&imm0, int s)
break;
case OP_MOD:
- if (i->sType == TYPE_U32 && imm0.isPow2()) {
+ if (s == 1 && imm0.isPow2()) {
bld.setPosition(i, false);
- i->op = OP_AND;
- i->setSrc(1, bld.loadImm(NULL, imm0.reg.data.u32 - 1));
+ if (i->sType == TYPE_U32) {
+ i->op = OP_AND;
+ i->setSrc(1, bld.loadImm(NULL, imm0.reg.data.u32 - 1));
+ } else if (i->sType == TYPE_S32) {
+ // Do it on the absolute value of the input, and then restore the
+ // sign. The only odd case is MIN_INT, but that should work out
+ // as well, since MIN_INT mod any power of 2 is 0.
+ //
+ // Technically we don't have to do any of this since MOD is
+ // undefined with negative arguments in GLSL, but this seems like
+ // the nice thing to do.
+ Value *abs = bld.mkOp1v(OP_ABS, TYPE_S32, bld.getSSA(),
i->getSrc(0));
+ Value *neg, *v1, *v2;
+ bld.mkCmp(OP_SET, CC_LT, TYPE_S32,
+ (neg = bld.getSSA(1,
prog->getTarget()->nativeFile(FILE_PREDICATE))),
+ TYPE_S32, i->getSrc(0), bld.loadImm(NULL, 0));
+ Value *mod = bld.mkOp2v(OP_AND, TYPE_U32, bld.getSSA(), abs,
+ bld.loadImm(NULL, imm0.reg.data.u32 - 1));
+ bld.mkOp1(OP_NEG, TYPE_S32, (v1 = bld.getSSA()), mod)
+ ->setPredicate(CC_P, neg);
+ bld.mkOp1(OP_MOV, TYPE_S32, (v2 = bld.getSSA()), mod)
+ ->setPredicate(CC_NOT_P, neg);
+ newi = bld.mkOp2(OP_UNION, TYPE_S32, i->getDef(0), v1, v2);
+
+ delete_Instruction(prog, i);
+ }
}
break;
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