From e32b9eb32d7cd2d39bf9c70497890ac61b9ee14c Mon Sep 17 00:00:00 2001
From: Richard Sandiford <richard.sandiford@arm.com>
Date: Tue, 30 Nov 2021 09:52:25 +0000
Subject: vect: Add support for fmax and fmin reductions

This patch adds support for reductions involving calls to fmax*()
and fmin*(), without the -ffast-math flags that allow them to be
converted to MAX_EXPR and MIN_EXPR.

gcc/
	* doc/md.texi (reduc_fmin_scal_@var{m}): Document.
	(reduc_fmax_scal_@var{m}): Likewise.
	* optabs.def (reduc_fmax_scal_optab): New optab.
	(reduc_fmin_scal_optab): Likewise
	* internal-fn.def (REDUC_FMAX, REDUC_FMIN): New functions.
	* tree-vect-loop.c (reduction_fn_for_scalar_code): Handle
	CASE_CFN_FMAX and CASE_CFN_FMIN.
	(neutral_op_for_reduction): Likewise.
	(needs_fold_left_reduction_p): Likewise.
	* config/aarch64/iterators.md (FMAXMINV): New iterator.
	(fmaxmin): Handle UNSPEC_FMAXNMV and UNSPEC_FMINNMV.
	* config/aarch64/aarch64-simd.md (reduc_<optab>_scal_<mode>): Fix
	unspec mode.
	(reduc_<fmaxmin>_scal_<mode>): New pattern.
	* config/aarch64/aarch64-sve.md (reduc_<fmaxmin>_scal_<mode>):
	Likewise.

gcc/testsuite/
	* gcc.dg/vect/vect-fmax-1.c: New test.
	* gcc.dg/vect/vect-fmax-2.c: Likewise.
	* gcc.dg/vect/vect-fmax-3.c: Likewise.
	* gcc.dg/vect/vect-fmin-1.c: New test.
	* gcc.dg/vect/vect-fmin-2.c: Likewise.
	* gcc.dg/vect/vect-fmin-3.c: Likewise.
	* gcc.target/aarch64/fmaxnm_1.c: Likewise.
	* gcc.target/aarch64/fmaxnm_2.c: Likewise.
	* gcc.target/aarch64/fminnm_1.c: Likewise.
	* gcc.target/aarch64/fminnm_2.c: Likewise.
	* gcc.target/aarch64/sve/fmaxnm_2.c: Likewise.
	* gcc.target/aarch64/sve/fmaxnm_3.c: Likewise.
	* gcc.target/aarch64/sve/fminnm_2.c: Likewise.
	* gcc.target/aarch64/sve/fminnm_3.c: Likewise.
---
 gcc/doc/md.texi | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'gcc/doc/md.texi')

diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index 589f841..8fd0f8d 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -5400,6 +5400,14 @@ Find the unsigned minimum/maximum of the elements of a vector. The vector is
 operand 1, and operand 0 is the scalar result, with mode equal to the mode of
 the elements of the input vector.
 
+@cindex @code{reduc_fmin_scal_@var{m}} instruction pattern
+@cindex @code{reduc_fmax_scal_@var{m}} instruction pattern
+@item @samp{reduc_fmin_scal_@var{m}}, @samp{reduc_fmax_scal_@var{m}}
+Find the floating-point minimum/maximum of the elements of a vector,
+using the same rules as @code{fmin@var{m}3} and @code{fmax@var{m}3}.
+Operand 1 is a vector of mode @var{m} and operand 0 is the scalar
+result, which has mode @code{GET_MODE_INNER (@var{m})}.
+
 @cindex @code{reduc_plus_scal_@var{m}} instruction pattern
 @item @samp{reduc_plus_scal_@var{m}}
 Compute the sum of the elements of a vector. The vector is operand 1, and
-- 
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