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| -rw-r--r-- | llvm/docs/Vectorizers.rst | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/llvm/docs/Vectorizers.rst b/llvm/docs/Vectorizers.rst index 4a015800741..8ac7ae0847d 100644 --- a/llvm/docs/Vectorizers.rst +++ b/llvm/docs/Vectorizers.rst @@ -311,7 +311,7 @@ ignored (as other compilers do) are still being left un-vectorized. Vectorization of function calls ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -The Loop Vectorize can vectorize intrinsic math functions. +The Loop Vectorizer can vectorize intrinsic math functions. See the table below for a list of these functions. +-----+-----+---------+ @@ -328,6 +328,11 @@ See the table below for a list of these functions. | | | fmuladd | +-----+-----+---------+ +Note that the optimizer may not be able to vectorize math library functions +that correspond to these intrinsics if the library calls access external state +such as "errno". To allow better optimization of C/C++ math library functions, +use "-fno-math-errno". + The loop vectorizer knows about special instructions on the target and will vectorize a loop containing a function call that maps to the instructions. For example, the loop below will be vectorized on Intel x86 if the SSE4.1 roundps @@ -340,10 +345,6 @@ instruction is available. f[i] = floorf(f[i]); } -Note that the optimizer may not be able to vectorize math library functions -that access external state such as "errno". To allow better optimization of -C/C++ math library functions, use "-fno-math-errno". - Partial unrolling during vectorization ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
