[gcc r12-2764] doc: Document cond_* shift optabs in md.texi

[gcc r12-2764] doc: Document cond_* shift optabs in md.texi

[Richard Sandiford]

https://gcc.gnu.org/g:c04bb6d93f3bd009800cb99e56c779a69d832691

commit r12-2764-gc04bb6d93f3bd009800cb99e56c779a69d832691
Author: Richard Sandiford <richard.sandiford@arm.com>
Date:   Thu Aug 5 14:03:24 2021 +0100

    doc: Document cond_* shift optabs in md.texi
    
    gcc/
            PR middle-end/101787
            * doc/md.texi (cond_ashl, cond_ashr, cond_lshr): Document.

Diff:
---
 gcc/doc/md.texi | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index f6d1bc1ad0f..f8047aefccc 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -6921,6 +6921,9 @@ operand 0, otherwise (operand 2 + operand 3) is moved.
 @cindex @code{cond_smax@var{mode}} instruction pattern
 @cindex @code{cond_umin@var{mode}} instruction pattern
 @cindex @code{cond_umax@var{mode}} instruction pattern
+@cindex @code{cond_ashl@var{mode}} instruction pattern
+@cindex @code{cond_ashr@var{mode}} instruction pattern
+@cindex @code{cond_lshr@var{mode}} instruction pattern
 @item @samp{cond_add@var{mode}}
 @itemx @samp{cond_sub@var{mode}}
 @itemx @samp{cond_mul@var{mode}}
@@ -6935,6 +6938,9 @@ operand 0, otherwise (operand 2 + operand 3) is moved.
 @itemx @samp{cond_smax@var{mode}}
 @itemx @samp{cond_umin@var{mode}}
 @itemx @samp{cond_umax@var{mode}}
+@itemx @samp{cond_ashl@var{mode}}
+@itemx @samp{cond_ashr@var{mode}}
+@itemx @samp{cond_lshr@var{mode}}
 When operand 1 is true, perform an operation on operands 2 and 3 and
 store the result in operand 0, otherwise store operand 4 in operand 0.
 The operation works elementwise if the operands are vectors.
@@ -6962,6 +6968,11 @@ Operands 0, 2, 3 and 4 all have mode @var{m}.  Operand 1 is a scalar
 integer if @var{m} is scalar, otherwise it has the mode returned by
 @code{TARGET_VECTORIZE_GET_MASK_MODE}.
 
+@samp{cond_@var{op}@var{mode}} generally corresponds to a conditional
+form of @samp{@var{op}@var{mode}3}.  As an exception, the vector forms
+of shifts correspond to patterns like @code{vashl@var{mode}3} rather
+than patterns like @code{ashl@var{mode}3}.
+
 @cindex @code{cond_fma@var{mode}} instruction pattern
 @cindex @code{cond_fms@var{mode}} instruction pattern
 @cindex @code{cond_fnma@var{mode}} instruction pattern