[Beignet] [PATCH] backend: add global immediate optimization
Pan, Xiuli
xiuli.pan at intel.com
Wed Jun 7 08:47:06 UTC 2017
The optimization idea is great, but the code structure maybe need refine.
If SelGlobalImmMovOpt is inherited from SelBasicBlockOptimizer, then the run should target for basic blocks.
And the imm cacluate optimization should not be mixed with the mov optimization. It can be a third optimization pass, and we should also refine the environment value to turn on or off these optimizations individually.
-----Original Message-----
From: Beignet [mailto:beignet-bounces at lists.freedesktop.org] On Behalf Of rander.wang
Sent: Saturday, May 27, 2017 10:43
To: beignet at freedesktop.org
Cc: Wang, Rander <rander.wang at intel.com>
Subject: [Beignet] [PATCH] backend: add global immediate optimization
there are some global immediates in global var list of LLVM.
these imm can be integrated in instructions. for compiler_global_immediate_optimized test
in utest, there are two global immediates:
L0:
MOV(1) %42<0>:UD : 0x0:UD
MOV(1) %43<0>:UD : 0x30:UD
used by:
ADD(16) %49<1>:D : %42<0,1,0>:D %48<8,8,1>:D
ADD(16) %54<1>:D : %43<0,1,0>:D %53<8,8,1>:D
it can be
ADD(16) %49<1>:D : %48<8,8,1>:D 0x0:UD
ADD(16) %54<1>:D : %53<8,8,1>:D 0x30:UD
Then the MOV can be removed. And after this optimization, ADD 0 can be change
to MOV, then local copy propagation can be done.
Signed-off-by: rander.wang <rander.wang at intel.com>
---
.../src/backend/gen_insn_selection_optimize.cpp | 278 ++++++++++++++++++++-
1 file changed, 277 insertions(+), 1 deletion(-)
diff --git a/backend/src/backend/gen_insn_selection_optimize.cpp b/backend/src/backend/gen_insn_selection_optimize.cpp
index d2e0fb9..bcaa583 100644
--- a/backend/src/backend/gen_insn_selection_optimize.cpp
+++ b/backend/src/backend/gen_insn_selection_optimize.cpp
@@ -64,7 +64,7 @@ namespace gbe
~SelBasicBlockOptimizer() {}
virtual void run();
- private:
+ protected:
// local copy propagation
class ReplaceInfo
{
@@ -90,6 +90,7 @@ namespace gbe
uint32_t elements;
const GenRegister& replacement;
set<GenRegister*> toBeReplaceds;
+ set<SelectionInstruction*> toBeReplacedInsns;
bool replacementOverwritten;
GBE_CLASS(ReplaceInfo);
};
@@ -114,6 +115,99 @@ namespace gbe
for (GenRegister* reg : info->toBeReplaceds) {
GenRegister::propagateRegister(*reg, info->replacement);
}
+
+ //after imm opt, maybe both src are imm, convert it to mov
+ for (SelectionInstruction* insn : info->toBeReplacedInsns) {
+ GenRegister& src0 = insn->src(0);
+ GenRegister& src1 = insn->src(1);
+ if (src0.file == GEN_IMMEDIATE_VALUE)
+ {
+ if (src1.file == GEN_IMMEDIATE_VALUE)
+ {
+ if (src0.type == GEN_TYPE_F)
+ {
+ float s0 = src0.value.f;
+ if (src0.absolute)
+ s0 = fabs(s0);
+ if (src0.negation)
+ s0 = -s0;
+
+ float s1 = src1.value.f;
+ if (src1.absolute)
+ s1 = fabs(s1);
+ if (src1.negation)
+ s1 = -s1;
+
+ float result;
+ switch(insn->opcode)
+ {
+ case SEL_OP_ADD:
+ result = s0 + s1;
+ break;
+ case SEL_OP_MUL:
+ result = s0 * s1;
+ break;
+ default:
+ assert(0);
+ break;
+ }
+
+ insn->src(0) = GenRegister::immf(result);
+ }
+ else if (src0.type == GEN_TYPE_D || src0.type == GEN_TYPE_UD)
+ {
+ int s0 = src0.value.d;
+ if (src0.absolute)
+ s0 = fabs(s0);
+ if (src0.negation)
+ s0 = -s0;
+
+ int s1 = src1.value.d;
+ if (src1.absolute)
+ s1 = fabs(s1);
+ if (src1.negation)
+ s1 = -s1;
+
+ int result;
+ switch(insn->opcode)
+ {
+ case SEL_OP_ADD:
+ result = s0 + s1;
+ break;
+ case SEL_OP_MUL:
+ result = s0 * s1;
+ break;
+ case SEL_OP_AND:
+ result = s0 & s1;
+ break;
+ case SEL_OP_OR:
+ result = s0 | s1;
+ break;
+ case SEL_OP_XOR:
+ result = s0 ^ s1;
+ break;
+ default:
+ assert(0);
+ break;
+ }
+
+ insn->src(0) = GenRegister::immd(result);
+ }
+
+ insn->opcode = SEL_OP_MOV;
+ insn->srcNum = 1;
+ }
+ else
+ {
+ //src0 cant be immediate, so exchange with src1
+ GenRegister tmp;
+ tmp = src0;
+ src0 = src1;
+ src1 = tmp;
+ }
+ }
+ }
+
bb.insnList.erase(&(info->insn));
optimized = true;
}
@@ -274,6 +368,184 @@ namespace gbe
virtual void run();
};
+ class SelGlobalImmMovOpt : public SelBasicBlockOptimizer {
+ public:
+ SelGlobalImmMovOpt(const GenContext& ctx, uint32_t features, intrusive_list<SelectionBlock> *blockList) :
+ SelBasicBlockOptimizer(ctx, ctx.getLiveOut((*blockList->begin()).bb), features, *blockList->begin())
+ {
+ mblockList = blockList;
+ }
+
+ virtual void run();
+
+ void addToReplaceInfoMap(SelectionInstruction& insn);
+ void doGlobalCopyPropagation();
+ bool CanBeReplaced(const ReplaceInfo* info, SelectionInstruction&
+ insn, const GenRegister& var);
+
+ private:
+ intrusive_list<SelectionBlock> *mblockList; };
+
+ extern void outputSelectionInst(SelectionInstruction &insn);
+
+ void SelGlobalImmMovOpt::addToReplaceInfoMap(SelectionInstruction&
+ insn) {
+ assert(insn.opcode == SEL_OP_MOV);
+ const GenRegister& src = insn.src(0);
+ const GenRegister& dst = insn.dst(0);
+ if (src.type != dst.type)
+ return;
+
+ ReplaceInfo* info = new ReplaceInfo(insn, dst, src);
+ replaceInfoMap[dst.reg()] = info;
+ }
+
+ bool SelGlobalImmMovOpt::CanBeReplaced(const ReplaceInfo* info,
+ SelectionInstruction& insn, const GenRegister& var) {
+ switch(insn.opcode)
+ {
+ // imm source is supported by these instructions. And
+ // the src operators can be exchange in these instructions
+ case SEL_OP_ADD:
+ case SEL_OP_MUL:
+ case SEL_OP_AND:
+ case SEL_OP_OR:
+ case SEL_OP_XOR:
+ break;
+ default:
+ return false;
+ }
+
+ if(info->intermedia.type != var.type)
+ {
+ bool isOk = false;
+ assert(info->replacement.file == GEN_IMMEDIATE_VALUE);
+ if(var.type == GEN_TYPE_D && info->intermedia.type == GEN_TYPE_UD)
+ {
+ if(info->replacement.value.ud >= 0x80000000)
+ return false;
+ isOk = true;
+ }
+
+ if(var.type == GEN_TYPE_UD && info->intermedia.type == GEN_TYPE_D)
+ {
+ if(info->replacement.value.d < 0)
+ return false;
+ isOk = true;
+ }
+
+ if(var.file == GEN_IMMEDIATE_VALUE)
+ isOk = false;
+
+ if(!isOk) return false;
+ }
+
+ if (info->intermedia.quarter == var.quarter &&
+ info->intermedia.subnr == var.subnr &&
+ info->intermedia.nr == var.nr)
+ {
+ uint32_t elements = CalculateElements(var, insn.state.execWidth); //considering width, hstrid, vstrid and execWidth
+ if (info->elements != elements)
+ return false;
+ }
+
+#ifdef DEBUG_GLOBAL_IMM_OPT
+ outputSelectionInst(insn);
+#endif
+
+ return true;
+ }
+
+ void SelGlobalImmMovOpt::doGlobalCopyPropagation()
+ {
+ for(SelectionBlock &block : *mblockList)
+ {
+ for (SelectionInstruction &insn :block.insnList)
+ {
+ for (uint8_t i = 0; i < insn.srcNum; ++i)
+ {
+ ReplaceInfoMap::iterator it = replaceInfoMap.find(insn.src(i).reg());
+ if (it != replaceInfoMap.end())
+ {
+ ReplaceInfo *info = it->second;
+ if (CanBeReplaced(info, insn, insn.src(i)))
+ {
+ info->toBeReplaceds.insert(&insn.src(i));
+ info->toBeReplacedInsns.insert(&insn);
+ }
+ else
+ {
+ replaceInfoMap.erase(it);
+ delete info;
+ }
+ }
+ }
+
+ for (uint8_t i = 0; i < insn.dstNum; ++i)
+ {
+ ReplaceInfoMap::iterator it = replaceInfoMap.find(insn.dst(i).reg());
+ if (it != replaceInfoMap.end())
+ {
+ ReplaceInfo *info = it->second;
+ if(&(info->insn) != &insn)
+ {
+ replaceInfoMap.erase(it);
+ delete info;
+ }
+ }
+ }
+ }
+
+ if(replaceInfoMap.empty())
+ break;
+ }
+
+ cleanReplaceInfoMap();
+ }
+
+ void SelGlobalImmMovOpt::run()
+ {
+ bool canbeOpt = false;
+
+ /*global immediates are set in entry block, the following is
+ example of GEN IR
+
+ decl_input.global %41 dst
+ ## 0 output register ##
+ ## 0 pushed register
+ ## 3 blocks ##
+ LABEL $0
+ LOADI.uint32 %42 0
+ LOADI.uint32 %43 48
+
+ LABEL $1
+ MUL.int32 %44 %3 %12
+ ADD.int32 %49 %42 %48
+ ...
+ */
+ SelectionBlock &block = *mblockList->begin();
+ for(SelectionInstruction &insn : block.insnList)
+ {
+ GenRegister src0 = insn.src(0);
+ if(insn.opcode == SEL_OP_MOV &&
+ src0.file == GEN_IMMEDIATE_VALUE &&
+ (src0.type == GEN_TYPE_UD || src0.type == GEN_TYPE_UD || src0.type == GEN_TYPE_F) &&
+ insn.state.predicate == GEN_PREDICATE_NONE)
+ {
+ addToReplaceInfoMap(insn);
+ canbeOpt = true;
+
+#ifdef DEBUG_GLOBAL_IMM_OPT
+ outputSelectionInst(insn);
+#endif
+ }
+ }
+
+ if(!canbeOpt) return;
+
+ doGlobalCopyPropagation();
+ }
+
void SelGlobalOptimizer::run()
{
@@ -281,6 +553,10 @@ namespace gbe
void Selection::optimize()
{
+ //do global imm opt first to make more local opt
+ SelGlobalImmMovOpt gopt(getCtx(), opt_features, blockList);
+ gopt.run();
+
//do basic block level optimization
for (SelectionBlock &block : *blockList) {
SelBasicBlockOptimizer bbopt(getCtx(), getCtx().getLiveOut(block.bb), opt_features, block);
--
2.7.4
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