diff options
Diffstat (limited to 'llvm/docs/LangRef.rst')
| -rw-r--r-- | llvm/docs/LangRef.rst | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst index 2cb71bb78ce..d588b0514b0 100644 --- a/llvm/docs/LangRef.rst +++ b/llvm/docs/LangRef.rst @@ -12361,6 +12361,31 @@ if"); and this allows for "check widening" type optimizations. ``@llvm.experimental.guard`` cannot be invoked. +'``llvm.load.relative``' Intrinsic +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Syntax: +""""""" + +:: + + declare i8* @llvm.load.relative.iN(i8* %ptr, iN %offset) argmemonly nounwind readonly + +Overview: +""""""""" + +This intrinsic loads a 32-bit value from the address ``%ptr + %offset``, +adds ``%ptr`` to that value and returns it. The constant folder specifically +recognizes the form of this intrinsic and the constant initializers it may +load from; if a loaded constant initializer is known to have the form +``i32 trunc(x - %ptr)``, the intrinsic call is folded to ``x``. + +LLVM provides that the calculation of such a constant initializer will +not overflow at link time under the medium code model if ``x`` is an +``unnamed_addr`` function. However, it does not provide this guarantee for +a constant initializer folded into a function body. This intrinsic can be +used to avoid the possibility of overflows when loading from such a constant. + Stack Map Intrinsics -------------------- |
