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Optimize DPI temporary 'for' loop performance (#6079) 

Signed-off-by: Bartłomiej Chmiel <bchmiel@antmicro.com>
This commit is contained in:
Bartłomiej Chmiel 2025-06-10 14:17:26 +02:00 committed by GitHub
parent 07394fcafa
commit 86d2ea8c70
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GPG Key ID: B5690EEEBB952194
1 changed files with 20 additions and 11 deletions
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31
src/V3Task.cpp
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@ -1944,6 +1944,7 @@ string V3Task::assignInternalToDpi(AstVar* portp, bool isPtr, const string& frSu
// But for now, we'll just text-bash it.
const string frName = frPrefix + portp->name() + frSuffix;
const string toName = portp->name() + toSuffix;
const string idx = portp->name() + "__Vidx";
size_t unpackSize = 1; // non-unpacked array is treated as size 1
int unpackDim = 0;
if (AstUnpackArrayDType* const unpackp
@ -1954,17 +1955,23 @@ string V3Task::assignInternalToDpi(AstVar* portp, bool isPtr, const string& frSu
}
if (portp->basicp()->isDpiBitVec() || portp->basicp()->isDpiLogicVec()) {
const bool isBit = portp->basicp()->isDpiBitVec();
const string idx = portp->name() + "__Vidx";
stmt = "for (size_t " + idx + " = 0; " + idx + " < " + cvtToStr(unpackSize) + "; ++" + idx
+ ") ";
const bool needsFor = unpackSize > 1;
if (needsFor) {
stmt = "for (size_t " + idx + " = 0; " + idx + " < " + cvtToStr(unpackSize) + "; ++"
+ idx + ") ";
}
stmt += (isBit ? "VL_SET_SVBV_"s : "VL_SET_SVLV_"s)
+ portp->dtypep()->skipRefp()->charIQWN() + "(" + cvtToStr(portp->width()) + ", ";
stmt += toName + " + " + cvtToStr(portp->dtypep()->skipRefp()->widthWords()) + " * " + idx
+ ", ";
stmt += toName;
if (needsFor) {
stmt += " + " + cvtToStr(portp->dtypep()->skipRefp()->widthWords()) + " * " + idx;
}
stmt += ", ";
if (unpackDim > 0) { // Access multi-dimensional array as a 1D array
stmt += "(&" + frName;
for (int i = 0; i < unpackDim; ++i) stmt += "[0]";
stmt += ")[" + idx + "])";
stmt += ")[" + (needsFor ? idx : "0") + "])";
} else {
stmt += frName + ")";
}
@ -1973,11 +1980,13 @@ string V3Task::assignInternalToDpi(AstVar* portp, bool isPtr, const string& frSu
= portp->basicp() && portp->basicp()->keyword() == VBasicDTypeKwd::CHANDLE;
const bool isString
= portp->basicp() && portp->basicp()->keyword() == VBasicDTypeKwd::STRING;
const string idx = portp->name() + "__Vidx";
stmt = "for (size_t " + idx + " = 0; " + idx + " < " + cvtToStr(unpackSize) + "; ++" + idx
+ ") ";
const string unpackAt = unpackSize > 1 ? "[" + idx + "]" : "[0]";
if (unpackDim > 0) {
stmt += toName + "[" + idx + "]";
const string forStmt = unpackSize > 1
? "for (size_t " + idx + " = 0; " + idx + " < "
+ cvtToStr(unpackSize) + "; ++" + idx + ") "
: "";
stmt += forStmt + toName + unpackAt;
} else {
if (isPtr) stmt += "*"; // DPI outputs are pointers
stmt += toName;
@ -1990,7 +1999,7 @@ string V3Task::assignInternalToDpi(AstVar* portp, bool isPtr, const string& frSu
if (unpackDim > 0) {
stmt += "(&" + frName;
for (int i = 0; i < unpackDim; ++i) stmt += "[0]";
stmt += ")[" + idx + "]";
stmt += ")" + unpackAt;
} else {
stmt += frName;
}