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Replace SET_VAR_AT_COMPILE_TIME with accel_tryUseCompileTimeValue #807

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Merged
TysonRayJones merged 1 commit into from
Jun 29, 2026
+118 −115
Merged

Replace SET_VAR_AT_COMPILE_TIME with accel_tryUseCompileTimeValue #807

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46 changes: 25 additions & 21 deletions quest/src/core/accelerator.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -24,11 +24,36 @@
#include "quest/include/qureg.h"
#include "quest/include/matrices.h"

#include "quest/src/core/inliner.hpp"
#include "quest/src/core/lists.hpp"

#include <vector>


/*
* COMPILE-TIME VARIABLES
*
* used by cpu_subroutines.cpp and gpu_subroutines to attemptedly set
* a variable to a value known at compile-time (like a templated function's
* parameter), enabling compile-time optimisations of subsequent code which
* uses the variable such a loop unrolling. If the value is not known at
* compile-time (CompileTimeValue==-1 which indicates a templated function has
* been called with more qubits than it has been explicitly instantiated and
* optimised for), the runtime value is used, precluding optimisations.
*
* TODO: this trick is likely not presently working in (stoopid) MSVC compilers!
*/

template<int CompileTimeValue>
INLINE constexpr int accel_tryUseCompileTimeValue(int runtimeValue) {

if constexpr (CompileTimeValue == -1)
return runtimeValue;
else
return CompileTimeValue;
}


/*
* TEMPLATE INSTANTIATION MACROS
*
Expand Down Expand Up @@ -124,27 +149,6 @@
template returntype funcname <-1,numtargs, conj, haspower> args;



/*
* COMPILE-TIME VARIABLE MACROS
*
* used by cpu_subroutines.cpp and gpu_subroutines to attemptedly set
* a variable to a value known at compile-time (like a templated function's
* parameter), enabling compile-time optimisations of subsequent code which
* uses the variable such a loop unrolling. If the value is not known at
* compile-time (compileval==-1 which indicates a templated function has
* been called with more qubits than it has been explicitly instantiated and
* optimised for), the runtime value is used, precluding optimisations.
*/

#define SET_VAR_AT_COMPILE_TIME(type, name, compileval, runtimeval) \
type name; \
if constexpr (compileval == -1) \
name = runtimeval; \
else \
name = compileval;


/*
* GETTERS
*/
Expand Down
60 changes: 27 additions & 33 deletions quest/src/cpu/cpu_subroutines.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -237,7 +237,7 @@ qindex cpu_statevec_packAmpsIntoBuffer(Qureg qureg, ConstList64 qubitInds, Const
auto qubitStateMask = util_getBitMask(qubitInds, qubitStates);

// use template param to compile-time unroll loop in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numBits, NumQubits, qubitInds.size());
int numBits = accel_tryUseCompileTimeValue<NumQubits>(qubitInds.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -309,8 +309,7 @@ void cpu_statevec_anyCtrlSwap_subA(Qureg qureg, ConstList64 ctrls, ConstList64 c
auto qubitStateMask = util_getBitMask(ctrls, ctrlStates, {targ2, targ1}, {0, 1});

// use template param to compile-time unroll loop in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
int numQubitBits = numCtrlBits + 2;
int numQubitBits = 2 + accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -344,7 +343,7 @@ void cpu_statevec_anyCtrlSwap_subB(Qureg qureg, ConstList64 ctrls, ConstList64 c
auto ctrlStateMask = util_getBitMask(ctrls, ctrlStates);

// use template param to compile-time unroll loop in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
int numCtrlBits = accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -381,8 +380,7 @@ void cpu_statevec_anyCtrlSwap_subC(Qureg qureg, ConstList64 ctrls, ConstList64 c
auto qubitStateMask = util_getBitMask(ctrls, ctrlStates, {targ}, {targState});

// use template param to compile-time unroll loop in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
int numQubitBits = numCtrlBits + 1;
int numQubitBits = 1 + accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -427,8 +425,7 @@ void cpu_statevec_anyCtrlOneTargDenseMatr_subA(Qureg qureg, ConstList64 ctrls, C
auto qubitStateMask = util_getBitMask(ctrls, ctrlStates, {targ}, {0});

// use template param to compile-time unroll loop in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
int numQubitBits = numCtrlBits + 1;
int numQubitBits = 1 + accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -469,7 +466,7 @@ void cpu_statevec_anyCtrlOneTargDenseMatr_subB(Qureg qureg, ConstList64 ctrls, C
auto ctrlStateMask = util_getBitMask(ctrls, ctrlStates);

// use template param to compile-time unroll loop in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
int numCtrlBits = accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -512,8 +509,7 @@ void cpu_statevec_anyCtrlTwoTargDenseMatr_sub(Qureg qureg, ConstList64 ctrls, Co
auto qubitStateMask = util_getBitMask(ctrls, ctrlStates, {targ1, targ2}, {0, 0});

// use template param to compile-time unroll loop in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
int numQubitBits = numCtrlBits + 2;
int numQubitBits = 2 + accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -585,12 +581,10 @@ void cpu_statevec_anyCtrlAnyTargDenseMatr_sub(Qureg qureg, ConstList64 ctrls, Co
auto qubitStateMask = util_getBitMask(ctrls, ctrlStates, targs, util_getConstantList(0,targs.size()));

// attempt to use compile-time variables to automatically optimise/unroll dependent loops
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
SET_VAR_AT_COMPILE_TIME(int, numTargBits, NumTargs, targs.size());

// compiler will infer these at compile-time if possible
int numCtrlBits = accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());
int numTargBits = accel_tryUseCompileTimeValue<NumTargs>(targs.size());
int numQubitBits = numCtrlBits + numTargBits;
qindex numTargAmps = powerOf2(numTargBits);
auto numTargAmps = powerOf2(numTargBits);

// create an explicit parallel region to avoid re-initialisation of vectors every iteration
#pragma omp parallel if(qureg.isMultithreaded)
Expand Down Expand Up @@ -678,7 +672,7 @@ void cpu_statevec_anyCtrlOneTargDiagMatr_sub(Qureg qureg, ConstList64 ctrls, Con
auto ctrlStateMask = util_getBitMask(ctrls, ctrlStates);

// use template params to compile-time unroll loops in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
int numCtrlBits = accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -721,7 +715,7 @@ void cpu_statevec_anyCtrlTwoTargDiagMatr_sub(Qureg qureg, ConstList64 ctrls, Con
auto ctrlStateMask = util_getBitMask(ctrls, ctrlStates);

// use template params to compile-time unroll loops in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
int numCtrlBits = accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -771,8 +765,8 @@ void cpu_statevec_anyCtrlAnyTargDiagMatr_sub(Qureg qureg, ConstList64 ctrls, Con
const bool areTargsSorted = util_isSorted(targs);

// use template params to compile-time unroll loops in insertBits() and getValueOfBits()
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
SET_VAR_AT_COMPILE_TIME(int, numTargBits, NumTargs, targs.size());
int numCtrlBits = accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());
int numTargBits = accel_tryUseCompileTimeValue<NumTargs>(targs.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -957,7 +951,7 @@ INLINE void applyPauliUponAmpPair(
// also being compiled (through the tests)... Hours of my life forever lost!

// remind compiler when NumTargs is compile-time to unroll loop in setBits()
SET_VAR_AT_COMPILE_TIME(int, numTargBits, NumTargs, numXY);
int numTargBits = accel_tryUseCompileTimeValue<NumTargs>(numXY);

// iA = nth local index where targs have value m, iB = (last - nth) such index
qindex iA = setBits(i0, indXY, numTargBits, v);
Expand Down Expand Up @@ -1004,12 +998,12 @@ void cpu_statevector_anyCtrlPauliTensorOrGadget_subA(
auto maskYZ = util_getBitMask(util_getConcatenated(y, z));

// use template params to compile-time unroll loops in insertBits() and inner-loop below
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
SET_VAR_AT_COMPILE_TIME(int, numTargBits, NumTargs, sortedTargsXY.size());
int numCtrlBits = accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());
int numTargBits = accel_tryUseCompileTimeValue<NumTargs>(sortedTargsXY.size());
int numQubitBits = numCtrlBits + numTargBits;

// each outer iteration handles all assignments of the target qubits, and each ctrl halves the outer iterations
qindex numOuterIts = qureg.numAmpsPerNode / powerOf2(numCtrlBits + numTargBits);
qindex numOuterIts = qureg.numAmpsPerNode / powerOf2(numQubitBits);

// each inner iteration modifies 2 amplitudes (may be compile-time sized)
qindex numInnerIts = powerOf2(numTargBits) / 2; // divides evenly
Expand Down Expand Up @@ -1088,7 +1082,7 @@ void cpu_statevector_anyCtrlPauliTensorOrGadget_subB(
auto maskYZ = util_getBitMask(util_getConcatenated(y, z));

// use template param to compile-time unroll loop in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
int numCtrlBits = accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -1139,7 +1133,7 @@ void cpu_statevector_anyCtrlAnyTargZOrPhaseGadget_sub(
auto targIndMask = util_getBitMask(targs);

// use template param to compile-time unroll loop in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numCtrlBits, NumCtrls, ctrls.size());
int numCtrlBits = accel_tryUseCompileTimeValue<NumCtrls>(ctrls.size());

#pragma omp parallel for if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -1173,7 +1167,7 @@ void cpu_statevec_setQuregToWeightedSum_sub(Qureg outQureg, vector<qcomp> coeffs
qindex numIts = outQureg.numAmpsPerNode;

// use template param to compile-time unroll inner loop below
SET_VAR_AT_COMPILE_TIME(int, numQuregs, NumQuregs, inQuregs.size());
int numQuregs = accel_tryUseCompileTimeValue<NumQuregs>(inQuregs.size());

#pragma omp parallel for if(outQureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -1888,10 +1882,10 @@ void cpu_densmatr_partialTrace_sub(Qureg inQureg, Qureg outQureg, ConstList64 ta
auto allTargsSorted = util_getSorted(targs, pairTargs);

// use template param to compile-time unroll below loops
SET_VAR_AT_COMPILE_TIME(int, numTargPairs, NumTargs, targs.size());
int numTargPairs = accel_tryUseCompileTimeValue<NumTargs>(targs.size());

// may be inferred at compile-time
int numAllTargs = 2*numTargPairs;
int numAllTargs = 2 * numTargPairs;
qindex numInnerIts = powerOf2(numTargPairs);

/// @todo
Expand Down Expand Up @@ -2027,7 +2021,7 @@ qreal cpu_statevec_calcProbOfMultiQubitOutcome_sub(Qureg qureg, ConstList64 qubi
auto qubitStateMask = util_getBitMask(qubits, outcomes);

// use template param to compile-time unroll loop in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numBits, NumQubits, qubits.size());
int numBits = accel_tryUseCompileTimeValue<NumQubits>(qubits.size());

#pragma omp parallel for reduction(+:prob) if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -2065,7 +2059,7 @@ qreal cpu_densmatr_calcProbOfMultiQubitOutcome_sub(Qureg qureg, ConstList64 qubi
auto qubitStateMask = util_getBitMask(qubits, outcomes);

// use template param to compile-time unroll loop in insertBits()
SET_VAR_AT_COMPILE_TIME(int, numBits, NumQubits, qubits.size());
int numBits = accel_tryUseCompileTimeValue<NumQubits>(qubits.size());

#pragma omp parallel for reduction(+:prob) if(qureg.isMultithreaded)
for (qindex n=0; n<numIts; n++) {
Expand Down Expand Up @@ -2099,7 +2093,7 @@ void cpu_statevec_calcProbsOfAllMultiQubitOutcomes_sub(qreal* outProbs, Qureg qu
const bool areQubitsSorted = util_isSorted(qubits);

// use template param to compile-time unroll loop in getValueOfBits()
SET_VAR_AT_COMPILE_TIME(int, numBits, NumQubits, qubits.size());
int numBits = accel_tryUseCompileTimeValue<NumQubits>(qubits.size());
qindex numOutcomes = powerOf2(numBits);

// decide whether to parallelise below amp-clearing, since outProbs ~ dim of a qureg
Expand Down Expand Up @@ -2146,7 +2140,7 @@ void cpu_densmatr_calcProbsOfAllMultiQubitOutcomes_sub(qreal* outProbs, Qureg qu
const bool areQubitsSorted = util_isSorted(qubits);

// use template param to compile-time unroll loop in getValueOfBits()
SET_VAR_AT_COMPILE_TIME(int, numBits, NumQubits, qubits.size());
int numBits = accel_tryUseCompileTimeValue<NumQubits>(qubits.size());
qindex numOutcomes = powerOf2(numBits);

// decide whether to parallelise below amp-clearing, since outProbs ~ dim of a qureg
Expand Down
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