I've checked in this patch for PR 21110. As noted in the issue, RTL
high and lo_sum expressions don't have to be Pmode and are not
restricted to address operands.
-Sandra
2018-11-12 Sandra Loosemore <san...@codesourcery.com>
PR middle-end/21110
gcc/
* doc/rtl.texi (Constants): Clarify that mode of "high" doesn't
have to be Pmode.
(Arithmetic): Likewise for "lo_sum".
Index: gcc/doc/rtl.texi
===================================================================
--- gcc/doc/rtl.texi (revision 266034)
+++ gcc/doc/rtl.texi (working copy)
@@ -1883,14 +1883,14 @@ of relocation operator. @var{m} should
@findex high
@item (high:@var{m} @var{exp})
-Represents the high-order bits of @var{exp}, usually a
-@code{symbol_ref}. The number of bits is machine-dependent and is
+Represents the high-order bits of @var{exp}.
+The number of bits is machine-dependent and is
normally the number of bits specified in an instruction that initializes
the high order bits of a register. It is used with @code{lo_sum} to
represent the typical two-instruction sequence used in RISC machines to
-reference a global memory location.
-
-@var{m} should be @code{Pmode}.
+reference large immediate values and/or link-time constants such
+as global memory addresses. In the latter case, @var{m} is @code{Pmode}
+and @var{exp} is usually a constant expression involving @code{symbol_ref}.
@end table
@findex CONST0_RTX
@@ -2429,15 +2429,15 @@ saturates at the maximum signed value re
This expression represents the sum of @var{x} and the low-order bits
of @var{y}. It is used with @code{high} (@pxref{Constants}) to
-represent the typical two-instruction sequence used in RISC machines
-to reference a global memory location.
+represent the typical two-instruction sequence used in RISC machines to
+reference large immediate values and/or link-time constants such
+as global memory addresses. In the latter case, @var{m} is @code{Pmode}
+and @var{y} is usually a constant expression involving @code{symbol_ref}.
The number of low order bits is machine-dependent but is
-normally the number of bits in a @code{Pmode} item minus the number of
+normally the number of bits in mode @var{m} minus the number of
bits set by @code{high}.
-@var{m} should be @code{Pmode}.
-
@findex minus
@findex ss_minus
@findex us_minus
