This patch amends the documentation for masked loads (maskload,
vec_mask_load_lanes, and mask_gather_load as well as their len
counterparts) with an else operand.
gcc/ChangeLog:
* doc/md.texi: Document masked load else operand.
---
gcc/doc/md.texi | 60 +++++++++++++++++++++++++++++++------------------
1 file changed, 38 insertions(+), 22 deletions(-)
diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index 5dc0d55edd6..4047d8f58fe 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -5017,8 +5017,9 @@ This pattern is not allowed to @code{FAIL}.
@item @samp{vec_mask_load_lanes@var{m}@var{n}}
Like @samp{vec_load_lanes@var{m}@var{n}}, but takes an additional
mask operand (operand 2) that specifies which elements of the destination
-vectors should be loaded. Other elements of the destination
-vectors are set to zero. The operation is equivalent to:
+vectors should be loaded. Operand 3 is an else operand similar to the one
+in @code{maskload}.
+The operation is equivalent to:
@smallexample
int c = GET_MODE_SIZE (@var{m}) / GET_MODE_SIZE (@var{n});
@@ -5028,7 +5029,7 @@ for (j = 0; j < GET_MODE_NUNITS (@var{n}); j++)
operand0[i][j] = operand1[j * c + i];
else
for (i = 0; i < c; i++)
- operand0[i][j] = 0;
+ operand0[i][j] = operand3;
@end smallexample
This pattern is not allowed to @code{FAIL}.
@@ -5036,16 +5037,20 @@ This pattern is not allowed to @code{FAIL}.
@cindex @code{vec_mask_len_load_lanes@var{m}@var{n}} instruction pattern
@item @samp{vec_mask_len_load_lanes@var{m}@var{n}}
Like @samp{vec_load_lanes@var{m}@var{n}}, but takes an additional
-mask operand (operand 2), length operand (operand 3) as well as bias operand
(operand 4)
-that specifies which elements of the destination vectors should be loaded.
-Other elements of the destination vectors are undefined. The operation is
equivalent to:
+mask operand (operand 2), length operand (operand 4) as well as bias operand
+(operand 5) that specifies which elements of the destination vectors should be
+loaded. Operand 3 is an else operand similar to the one in @code{maskload}.
+Other elements of the destination vectors are undefined. The operation
+is equivalent to:
@smallexample
int c = GET_MODE_SIZE (@var{m}) / GET_MODE_SIZE (@var{n});
-for (j = 0; j < operand3 + operand4; j++)
- if (operand2[j])
- for (i = 0; i < c; i++)
+for (j = 0; j < operand4 + operand5; j++)
+ for (i = 0; i < c; i++)
+ if (operand2[j])
operand0[i][j] = operand1[j * c + i];
+ else
+ operand0[i][j] = operand3;
@end smallexample
This pattern is not allowed to @code{FAIL}.
@@ -5125,18 +5130,24 @@ address width.
@cindex @code{mask_gather_load@var{m}@var{n}} instruction pattern
@item @samp{mask_gather_load@var{m}@var{n}}
Like @samp{gather_load@var{m}@var{n}}, but takes an extra mask operand as
-operand 5. Bit @var{i} of the mask is set if element @var{i}
+operand 5 and an else operand 6 similar to the one in @code{maskload}.
+Bit @var{i} of the mask is set if element @var{i}
of the result should be loaded from memory and clear if element @var{i}
-of the result should be set to zero.
+of the result should be set to operand 6.
@cindex @code{mask_len_gather_load@var{m}@var{n}} instruction pattern
@item @samp{mask_len_gather_load@var{m}@var{n}}
-Like @samp{gather_load@var{m}@var{n}}, but takes an extra mask operand
(operand 5),
-a len operand (operand 6) as well as a bias operand (operand 7). Similar to
mask_len_load,
-the instruction loads at most (operand 6 + operand 7) elements from memory.
+Like @samp{gather_load@var{m}@var{n}}, but takes an extra mask operand
+(operand 5) and an else operand (operand 6) similar to the one in
+@code{maskload} as well as a len operand (operand 7) and a bias operand
+(operand 8).
+
+Similar to mask_len_load the instruction loads at
+most (operand 7 + operand 8) elements from memory.
Bit @var{i} of the mask is set if element @var{i} of the result should
-be loaded from memory and clear if element @var{i} of the result should be
undefined.
-Mask elements @var{i} with @var{i} > (operand 6 + operand 7) are ignored.
+be loaded from memory and clear if element @var{i} of the result should
+be set to operand 6.
+Mask elements @var{i} with @var{i} > (operand 7 + operand 8) are ignored.
@cindex @code{scatter_store@var{m}@var{n}} instruction pattern
@item @samp{scatter_store@var{m}@var{n}}
@@ -5368,8 +5379,12 @@ Operands 4 and 5 have a target-dependent scalar integer
mode.
@cindex @code{maskload@var{m}@var{n}} instruction pattern
@item @samp{maskload@var{m}@var{n}}
Perform a masked load of vector from memory operand 1 of mode @var{m}
-into register operand 0. Mask is provided in register operand 2 of
-mode @var{n}.
+into register operand 0. The mask is provided in register operand 2 of
+mode @var{n}. Operand 3 (the "else value") specifies which value is loaded
+when the mask is unset. The predicate of operand 3 must only accept
+the else values that the target actually supports. Currently two values
+are attempted, zero and undefined. GCC handles an else value of zero more
+efficiently than an undefined one.
This pattern is not allowed to @code{FAIL}.
@@ -5435,15 +5450,16 @@ Operands 0 and 1 have mode @var{m}, which must be a
vector mode. Operand 3
has whichever integer mode the target prefers. A mask is specified in
operand 2 which must be of type @var{n}. The mask has lower precedence than
the length and is itself subject to length masking,
-i.e. only mask indices < (operand 3 + operand 4) are used.
+i.e. only mask indices < (operand 4 + operand 5) are used.
+Operand 3 is an else operand similar to the one in @code{maskload}.
Operand 4 conceptually has mode @code{QI}.
-Operand 2 can be a variable or a constant amount. Operand 4 specifies a
+Operand 2 can be a variable or a constant amount. Operand 5 specifies a
constant bias: it is either a constant 0 or a constant -1. The predicate on
-operand 4 must only accept the bias values that the target actually supports.
+operand 5 must only accept the bias values that the target actually supports.
GCC handles a bias of 0 more efficiently than a bias of -1.
-If (operand 2 + operand 4) exceeds the number of elements in mode
+If (operand 2 + operand 4 + operand 5) exceeds the number of elements in mode
@var{m}, the behavior is undefined.
If the target prefers the length to be measured in bytes
--
2.45.2
