Author: Karthika Devi C Date: 2026-07-16T16:27:11Z New Revision: 23780df286c2e5914014d002206f1bfde7d0f1b9
URL: https://github.com/llvm/llvm-project/commit/23780df286c2e5914014d002206f1bfde7d0f1b9 DIFF: https://github.com/llvm/llvm-project/commit/23780df286c2e5914014d002206f1bfde7d0f1b9.diff LOG: [Polly] Fix codegen assertions to account for DefinedBehaviorContext (#209188) DeLICM may produce new read access relations whose domain is restricted to the DefinedBehaviorContext (e.g., only valid when a parameter ensures no UB). The validation in setNewAccessRelation already accounts for this, but the debug assertions in createNewAccesses and generateScalarLoads did not, causing false assertion failures during code generation. Intersect the checked domains with getBestKnownDefinedBehaviorContext() to match the contract that DeLICM relies on. Fixes #205732 (cherry picked from commit ea612545644d1e3f238ac4cd053758f569f9bf3b) Added: polly/test/CodeGen/issue205732.ll Modified: polly/lib/CodeGen/BlockGenerators.cpp polly/lib/CodeGen/IslNodeBuilder.cpp Removed: ################################################################################ diff --git a/polly/lib/CodeGen/BlockGenerators.cpp b/polly/lib/CodeGen/BlockGenerators.cpp index be01f24f562b2..877bb48ad650a 100644 --- a/polly/lib/CodeGen/BlockGenerators.cpp +++ b/polly/lib/CodeGen/BlockGenerators.cpp @@ -555,6 +555,11 @@ void BlockGenerator::generateScalarLoads( #ifndef NDEBUG auto StmtDom = Stmt.getDomain().intersect_params(Stmt.getParent()->getContext()); + // Restrict to defined behavior context to match DeLICM's contract: + // new read accesses are only required to cover the defined-behavior + // subset of the domain. + StmtDom = StmtDom.intersect_params( + Stmt.getParent()->getBestKnownDefinedBehaviorContext()); auto AccDom = MA->getAccessRelation().domain(); assert(!StmtDom.is_subset(AccDom).is_false() && "Scalar must be loaded in all statement instances"); diff --git a/polly/lib/CodeGen/IslNodeBuilder.cpp b/polly/lib/CodeGen/IslNodeBuilder.cpp index 7e395fd4cbd31..93822e5c61615 100644 --- a/polly/lib/CodeGen/IslNodeBuilder.cpp +++ b/polly/lib/CodeGen/IslNodeBuilder.cpp @@ -846,9 +846,17 @@ IslNodeBuilder::createNewAccesses(ScopStmt *Stmt, Stmt->getParent()->getContext().release()); SchedDom = isl_set_intersect_params( SchedDom, Stmt->getParent()->getContext().release()); - assert(isl_set_is_subset(SchedDom, AccDom) && + // Restrict to defined behavior context to match DeLICM's contract: + // new read accesses are only required to cover the defined-behavior + // subset of the domain. + auto *DefinedBehavior = + Stmt->getParent()->getBestKnownDefinedBehaviorContext().release(); + SchedDom = + isl_set_intersect_params(SchedDom, isl_set_copy(DefinedBehavior)); + Dom = isl_set_intersect_params(Dom, DefinedBehavior); + assert(isl_set_is_subset(SchedDom, AccDom) != isl_bool_false && "Access relation not defined on full schedule domain"); - assert(isl_set_is_subset(Dom, AccDom) && + assert(isl_set_is_subset(Dom, AccDom) != isl_bool_false && "Access relation not defined on full domain"); isl_set_free(AccDom); isl_set_free(SchedDom); diff --git a/polly/test/CodeGen/issue205732.ll b/polly/test/CodeGen/issue205732.ll new file mode 100644 index 0000000000000..35dc786df1c4b --- /dev/null +++ b/polly/test/CodeGen/issue205732.ll @@ -0,0 +1,40 @@ +; RUN: opt %loadNPMPolly -passes=polly -S %s | FileCheck %s +; +; https://github.com/llvm/llvm-project/issues/205732 +; When DeLICM maps a scalar to an array element, the new access relation +; may only be valid within the DefinedBehaviorContext (i.e., for parameter +; values where the original program has no undefined behavior). Code +; generation must not assert failure for such partial-domain read accesses. +; +; CHECK: polly.start: + +define void @foo(i32 %w, ptr %dst, i64 %n) { +entry: + br label %for.outer + +for.outer: + %i = phi i64 [ %i.next, %for.mid.exit ], [ 0, %entry ] + br label %for.mid + +for.mid: + br label %for.inner + +for.inner: + %0 = phi i32 [ 0, %for.mid ], [ 1, %for.inner ] + %1 = load i16, ptr null, align 2 + %cond1 = icmp eq i32 0, %w + br i1 %cond1, label %for.inner.exit, label %for.inner + +for.inner.exit: + br i1 true, label %for.mid.exit, label %for.mid + +for.mid.exit: + %ptr = getelementptr [4 x i8], ptr %dst, i64 %i + store i32 %0, ptr %ptr, align 4 + %i.next = add i64 %i, 1 + %cond2 = icmp eq i64 %i, %n + br i1 %cond2, label %for.outer.exit, label %for.outer + +for.outer.exit: + ret void +} _______________________________________________ llvm-branch-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
