[clang] Restrict the use of scalar types in vector builtins (#119423) #10646
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) This commit restricts the use of scalar types in vector math builtins, particularly the `__builtin_elementwise_*` builtins. Previously, small scalar integer types would be promoted to `int`, as per the usual conversions. This would silently do the wrong thing for certain operations, such as `add_sat`, `popcount`, `bitreverse`, and others. Similarly, since unsigned integer types were promoted to `int`, something like `add_sat(unsigned char, unsigned char)` would perform a *signed* operation. With this patch, promotable scalar integer types are not promoted to int, and are kept intact. If any of the types differ in the binary and ternary builtins, an error is issued. Similarly an error is issued if builtins are supplied integer types of different signs. Mixing enums of different types in binary/ternary builtins now consistently raises an error in all language modes. This brings the behaviour surrounding scalar types more in line with that of vector types. No change is made to vector types, which are both not promoted and whose element types must match. Fixes llvm#84047. RFC: https://discourse.llvm.org/t/rfc-change-behaviour-of-elementwise-builtins-on-scalar-integer-types/83725
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@swift-ci please test |
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This commit restricts the use of scalar types in vector math builtins, particularly the
__builtin_elementwise_*builtins.Previously, small scalar integer types would be promoted to
int, as per the usual conversions. This would silently do the wrong thing for certain operations, such asadd_sat,popcount,bitreverse, and others. Similarly, since unsigned integer types were promoted toint, something likeadd_sat(unsigned char, unsigned char)would perform a signed operation.With this patch, promotable scalar integer types are not promoted to int, and are kept intact. If any of the types differ in the binary and ternary builtins, an error is issued. Similarly an error is issued if builtins are supplied integer types of different signs. Mixing enums of different types in binary/ternary builtins now consistently raises an error in all language modes.
This brings the behaviour surrounding scalar types more in line with that of vector types. No change is made to vector types, which are both not promoted and whose element types must match.
Fixes llvm#84047.
RFC:
https://discourse.llvm.org/t/rfc-change-behaviour-of-elementwise-builtins-on-scalar-integer-types/83725
rdar://117484572