https://github.com/yronglin created https://github.com/llvm/llvm-project/pull/90240
This PR fix the issue reported by @alexfh PR https://github.com/llvm/llvm-project/pull/89567 fix the `#pragma unroll N` crash issue in dependent context, but it's introduce an new issue: If `N` is value dependent, the `LoopHintAttr::Option` should be `LoopHintAttr::UnrollCount` and `LoopHintAttr::LoopHintState` should be `LoopHintAttr::Numeric`, but since https://github.com/llvm/llvm-project/pull/89567, these two flags was ` (LoopHintAttr::Unroll, LoopHintAttr::Enable)`. Therefor, clang's code generator generated incorrect IR metadata. ``` #include <cstddef> #include <bit> template <bool Flag> int FailToBuild(int n) { constexpr int N = 100; auto init = [=]() { return Flag ? n : 0UL; }; auto cond = [=](size_t ix) { return Flag ? ix != 0 : ix < 10; }; auto iter = [=](size_t ix) { return Flag ? ix & ~(1ULL << std::countr_zero(ix)) : ix + 1; }; #pragma unroll Flag ? 1 : N for (size_t ix = init(); cond(ix); ix = iter(ix)) { n *= n; } #pragma unroll Flag ? 0 : N // since #89567, error: invalid value '0'; must be positive for (size_t ix = init(); cond(ix); ix = iter(ix)) { n *= n; } return n; } int foo(int n) { return FailToBuild<true>(n); } int bar(int n) { return FailToBuild<false>(n); } ``` >From 131783211a23d007b5b6f1d5691306df4dec716b Mon Sep 17 00:00:00 2001 From: yronglin <yronglin...@gmail.com> Date: Sat, 27 Apr 2024 01:38:34 +0800 Subject: [PATCH] [Clang] Fix incorrect handling of #pragma {GCC} unroll N in dependent context Signed-off-by: yronglin <yronglin...@gmail.com> --- clang/lib/Sema/SemaStmtAttr.cpp | 23 ++++++++++-------- clang/test/Parser/pragma-unroll.cpp | 37 +++++++++++++++++++++++++++++ 2 files changed, 50 insertions(+), 10 deletions(-) diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp index 9d44c22c8ddcc3..4dfdfd7aec425f 100644 --- a/clang/lib/Sema/SemaStmtAttr.cpp +++ b/clang/lib/Sema/SemaStmtAttr.cpp @@ -109,16 +109,19 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const ParsedAttr &A, SetHints(LoopHintAttr::Unroll, LoopHintAttr::Disable); } else if (PragmaName == "unroll") { // #pragma unroll N - if (ValueExpr && !ValueExpr->isValueDependent()) { - llvm::APSInt ValueAPS; - ExprResult R = S.VerifyIntegerConstantExpression(ValueExpr, &ValueAPS); - assert(!R.isInvalid() && "unroll count value must be a valid value, it's " - "should be checked in Sema::CheckLoopHintExpr"); - (void)R; - // The values of 0 and 1 block any unrolling of the loop. - if (ValueAPS.isZero() || ValueAPS.isOne()) - SetHints(LoopHintAttr::UnrollCount, LoopHintAttr::Disable); - else + if (ValueExpr) { + if (!ValueExpr->isValueDependent()) { + llvm::APSInt ValueAPS; + ExprResult R = S.VerifyIntegerConstantExpression(ValueExpr, &ValueAPS); + assert(!R.isInvalid() && "unroll count value must be a valid value, it's " + "should be checked in Sema::CheckLoopHintExpr"); + (void)R; + // The values of 0 and 1 block any unrolling of the loop. + if (ValueAPS.isZero() || ValueAPS.isOne()) + SetHints(LoopHintAttr::UnrollCount, LoopHintAttr::Disable); + else + SetHints(LoopHintAttr::UnrollCount, LoopHintAttr::Numeric); + } else SetHints(LoopHintAttr::UnrollCount, LoopHintAttr::Numeric); } else SetHints(LoopHintAttr::Unroll, LoopHintAttr::Enable); diff --git a/clang/test/Parser/pragma-unroll.cpp b/clang/test/Parser/pragma-unroll.cpp index f41bd7a18d5a41..e84f6ea9ad1035 100644 --- a/clang/test/Parser/pragma-unroll.cpp +++ b/clang/test/Parser/pragma-unroll.cpp @@ -124,3 +124,40 @@ void test(int *List, int Length) { #pragma unroll /* expected-error {{expected statement}} */ } + +using size_t = unsigned long long; + +template <bool Flag> +int FailToBuild(int n) { + constexpr int N = 100; + auto init = [=]() { return Flag ? n : 0UL; }; + auto cond = [=](size_t ix) { return Flag ? ix != 0 : ix < 10; }; + auto iter = [=](size_t ix) { + return Flag ? ix & ~(1ULL << __builtin_clzll(ix)) : ix + 1; + }; +#pragma unroll Flag ? 1 : N + for (size_t ix = init(); cond(ix); ix = iter(ix)) { + n *= n; + } +#pragma unroll Flag ? 0 : N + for (size_t ix = init(); cond(ix); ix = iter(ix)) { + n *= n; + } +#pragma GCC unroll Flag ? 1 : N + for (size_t ix = init(); cond(ix); ix = iter(ix)) { + n *= n; + } +#pragma GCC unroll Flag ? 0 : N + for (size_t ix = init(); cond(ix); ix = iter(ix)) { + n *= n; + } + return n; +} + +int foo(int n) { + return FailToBuild<true>(n); +} + +int bar(int n) { + return FailToBuild<false>(n); +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
