IR: Add immarg attribute
This indicates an intrinsic parameter is required to be a constant,
and should not be replaced with a non-constant value.
Add the attribute to all AMDGPU and generic intrinsics that comments
indicate it should apply to. I scanned other target intrinsics, but I
don't see any obvious comments indicating which arguments are intended
to be only immediates.
This breaks one questionable testcase for the autoupgrade. I'm unclear
on whether the autoupgrade is supposed to really handle declarations
which were never valid. The verifier fails because the attributes now
refer to a parameter past the end of the argument list.
llvm-svn: 355981
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 261d1d4..009f855 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -1178,6 +1178,13 @@
does not alias any other memory visible within a function and that a
``swifterror`` alloca passed as an argument does not escape.
+``immarg``
+ This indicates the parameter is required to be an immediate
+ value. This must be a trivial immediate integer or floating-point
+ constant. Undef or constant expressions are not valid. This is
+ only valid on intrinsic declarations and cannot be applied to a
+ call site or arbitrary function.
+
.. _gc:
Garbage Collector Strategy Names