[PATCH] D78576: [SVE] Make VectorType::getNumElements() complain for scalable vectors
Christopher Tetreault via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Apr 21 10:48:17 PDT 2020
ctetreau created this revision.
Herald added subscribers: llvm-commits, psnobl, rkruppe, tschuett, mgorny.
Herald added a reviewer: efriedma.
Herald added a project: LLVM.
ctetreau added reviewers: sdesmalen, c-rhodes.
ctetreau added a parent revision: D77587: [SVE] Add new VectorType subclasses.
Piggy-back off of TypeSize's STRICT_FIXED_SIZE_VECTORS flag and:
- if it is defined, assert that the vector is not scalable
- if it is not defined, complain if the vector is scalable
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D78576
Files:
llvm/CMakeLists.txt
llvm/include/llvm/IR/DerivedTypes.h
Index: llvm/include/llvm/IR/DerivedTypes.h
===================================================================
--- llvm/include/llvm/IR/DerivedTypes.h
+++ llvm/include/llvm/IR/DerivedTypes.h
@@ -417,7 +417,21 @@
/// Get the number of elements in this vector. It does not make sense to call
/// this function on a scalable vector, and this will be moved into
/// FixedVectorType in a future commit
- unsigned getNumElements() const { return EC.Min; }
+ unsigned getNumElements() const {
+ ElementCount EC = getElementCount();
+#ifdef STRICT_FIXED_SIZE_VECTORS
+ assert(!EC.Scalable &&
+ "Request for fixed number of elements from scalable vector");
+ return EC.Min;
+#else
+ if (EC.Scalable)
+ WithColor::warning()
+ << "The code that requested the fixed number of elements has made "
+ "the assumption that this vector is not scalable. This assumption "
+ "was not correct, and this may lead to broken code\n";
+ return EC.Min;
+#endif
+ }
Type *getElementType() const { return ContainedType; }
Index: llvm/CMakeLists.txt
===================================================================
--- llvm/CMakeLists.txt
+++ llvm/CMakeLists.txt
@@ -415,15 +415,16 @@
option(LLVM_ENABLE_EXPENSIVE_CHECKS "Enable expensive checks" OFF)
# While adding scalable vector support to LLVM, we temporarily want to
-# allow an implicit conversion of TypeSize to uint64_t. This CMake flag
-# enables a more strict conversion where it asserts that the type is not
-# a scalable vector type.
+# allow an implicit conversion of TypeSize to uint64_t, and to allow
+# code to get the fixed number of elements from a possibly scalable vector.
+# This CMake flag enables a more strict mode where it asserts that the type
+# is not a scalable vector type.
#
# Enabling this flag makes it easier to find cases where the compiler makes
# assumptions on the size being 'fixed size', when building tests for
# SVE/SVE2 or other scalable vector architectures.
option(LLVM_ENABLE_STRICT_FIXED_SIZE_VECTORS
- "Enable assertions that type is not scalable in implicit conversion from TypeSize to uint64_t" OFF)
+ "Enable assertions that type is not scalable in implicit conversion from TypeSize to uint64_t and calls to getNumElements" OFF)
set(LLVM_ABI_BREAKING_CHECKS "WITH_ASSERTS" CACHE STRING
"Enable abi-breaking checks. Can be WITH_ASSERTS, FORCE_ON or FORCE_OFF.")
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