avoid Clang <= 10 bug with -fno-lax-vector-conversions (#14168)
Issue reported here:
https://discord.com/channels/689900678990135345/689932666505920596/1121124198593609728
```
/home/iree/runtime/src/iree/builtins/ukernel/arch/arm_64/mmt4d_arm_64_dotprod.c:63:12: error: initializing 'int32x4_t' (vector of 4 'int32_t' values) with an expression of incompatible type '__attribute__((__vector_size__(4 * sizeof(uint32_t)))) uint32_t' (vector of 4 'uint32_t' values)
acc0 = vdotq_lane_s32(acc0, rhs0, vget_low_s8(lhs0), 0);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/llvm-10/lib/clang/10.0.0/include/arm_neon.h:37021:11: note: expanded from macro 'vdotq_lane_s32'
int32x4_t __reint1 = __builtin_shufflevector(*(uint32x2_t *) &__reint, *(uint32x2_t *) &__reint, __p3, __p3, __p3, __p3); \
```
The problem is that Clang <= 10 incorrectly thinks that the return type
of `vdotq_lane_s32` is `uint32x4_t` when it's really `int32x4_t`.diff --git a/build_tools/cmake/iree_copts.cmake b/build_tools/cmake/iree_copts.cmake
index 0687050..a3940a7 100644
--- a/build_tools/cmake/iree_copts.cmake
+++ b/build_tools/cmake/iree_copts.cmake
@@ -199,7 +199,10 @@
"-Wunused-comparison"
"-Wvla"
+ CLANG_GTE_12
# Clang is lax by default on SIMD vector typing. GCC is strict by default.
+ # Some Clang's circa version 10 had incorrect return types for some
+ # intrinsics (#14168).
"-fno-lax-vector-conversions"
# TODO(#6959): Enable -Werror once we have a presubmit CI.
diff --git a/build_tools/cmake/iree_macros.cmake b/build_tools/cmake/iree_macros.cmake
index a2e7dc7..fa97034 100644
--- a/build_tools/cmake/iree_macros.cmake
+++ b/build_tools/cmake/iree_macros.cmake
@@ -304,7 +304,7 @@
_IREE_SELECTS
""
""
- "ALL;CLANG;CLANG_GTE_10;CLANG_CL;MSVC;GCC;CLANG_OR_GCC;MSVC_OR_CLANG_CL"
+ "ALL;CLANG;CLANG_GTE_10;CLANG_GTE_12;CLANG_CL;MSVC;GCC;CLANG_OR_GCC;MSVC_OR_CLANG_CL"
)
# OPTS is a variable containing the *name* of the variable being populated, so
# we need to dereference it twice.
@@ -322,6 +322,9 @@
if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 10)
list(APPEND _OPTS ${_IREE_SELECTS_CLANG_GTE_10})
endif()
+ if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 12)
+ list(APPEND _OPTS ${_IREE_SELECTS_CLANG_GTE_12})
+ endif()
list(APPEND _OPTS ${_IREE_SELECTS_CLANG_OR_GCC})
endif()
elseif("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
