================
@@ -50,26 +51,133 @@ struct LibOptPass : public impl::LibOptBase<LibOptPass> {
// Raw libopt option string forwarded by the frontend. This will later
control
// which optimizations the pass enables.
std::string optimizationOptions;
-
- /// Tracks current module.
- ModuleOp theModule;
};
} // namespace
mlir::LogicalResult LibOptPass::initializeOptions(
llvm::StringRef options,
- llvm::function_ref<mlir::LogicalResult(const llvm::Twine &)> errorHandler)
{
- (void)errorHandler;
+ llvm::function_ref<mlir::LogicalResult(const llvm::Twine &)>) {
optimizationOptions = options.str();
// TODO(cir): Parse options to select the active transformations for the
// pass.
return mlir::success();
}
+static void rewriteStdFindToMemchr(StdFindOp findOp,
+ mlir::SymbolTableCollection &symbolTables) {
+ auto iterTy = mlir::dyn_cast<cir::PointerType>(findOp.getResult().getType());
+ if (!iterTy || iterTy.getAddrSpace())
+ return;
+ auto elemTy = mlir::dyn_cast<cir::IntType>(iterTy.getPointee());
+ if (!elemTy || elemTy.getWidth() != 8)
+ return;
+
+ auto patternPtrTy =
+ mlir::dyn_cast<cir::PointerType>(findOp.getPattern().getType());
+ if (!patternPtrTy || patternPtrTy.getPointee() != elemTy)
+ return;
+
+ // LibOpt runs before LoweringPrepare, so a global initializer is still a
+ // cir.global here. Anything else is not a shape CIRGen produces.
+ auto enclosing = findOp->getParentOfType<cir::FuncOp>();
+ auto enclosingGlobal = findOp->getParentOfType<cir::GlobalOp>();
+ if (!enclosing && !enclosingGlobal)
+ return;
+
+ // No builtin state rides on the raised call and on the enclosing function.
+ // A global initializer has no function to carry the list.
+ if (isNoBuiltin(findOp, "memchr") ||
+ (enclosing && noBuiltinListDisables(enclosing, "memchr")))
+ return;
+
+ // An enum or atomic element also lowers to a byte wide integer.
+ auto callee = symbolTables.lookupNearestSymbolFrom<cir::FuncOp>(
+ findOp, findOp.getOriginalFnAttr());
+ auto funcIdentity = mlir::dyn_cast_if_present<cir::FuncIdentityAttr>(
+ callee ? callee.getFuncInfoAttr() : mlir::Attribute());
+ if (!funcIdentity || funcIdentity.getKind() != cir::KnownFuncKind::StdFind ||
+ !funcIdentity.getNarrowCharParams()) {
+ return;
+ }
+
+ auto moduleOp = findOp->getParentOfType<mlir::ModuleOp>();
+ if (!moduleOp)
+ return;
+
+ auto tripleAttr = moduleOp->getAttrOfType<mlir::StringAttr>(
+ cir::CIRDialect::getTripleAttrName());
+ if (!tripleAttr)
+ return;
+
+ llvm::Triple triple(tripleAttr.getValue().str());
+
+ // cir.libc.memchr currently requires a 64 bit length. Use the AST size_t
+ // width recorded by CIRGen instead of inferring it from target properties.
+ auto sizeWidthAttr = moduleOp->getAttrOfType<mlir::IntegerAttr>(
+ cir::CIRDialect::getSizeTypeWidthAttrName());
+ bool sizeTypeMismatch = !sizeWidthAttr ||
+ !sizeWidthAttr.getType().isSignlessInteger(32) ||
+ sizeWidthAttr.getInt() != 64;
+
+ // The current memchr lowering supplies no target ABI extension attributes,
so
+ // restrict the rewrite to targets known not to need them.
+ // TODO(cir): use target-aware ABI and libcall availability information.
+ bool abiSafeTarget =
+ triple.getArch() == llvm::Triple::x86_64 || triple.isAArch64();
+
+ // AArch64 GNUILP32 AST types disagree with LLVM's data layout.
+ bool unsupportedABI =
+ triple.isAArch64() && triple.getEnvironment() == llvm::Triple::GNUILP32;
+
+ if (sizeTypeMismatch || !abiSafeTarget || unsupportedABI)
+ return;
+
+ // Lowering resolves memchr in the module symbol table. An existing symbol
may
+ // collide with the introduced libcall or carry incompatible semantics.
+ if (symbolTables.lookupSymbolIn(
----------------
SharmaRithik wrote:
I did confirm this and a single ordinary memchr call blocks the rewrite so you
are right that the guard is too broad. The cases that motivated it used false
noreturn or returns_nonnull promises. My current plan is to follow the normal
libcall policy by checking availability and a compatible function prototype
while keeping the no builtin handling. I would appreciate any suggestions if
another approach fits CIR better.
https://github.com/llvm/llvm-project/pull/212355
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