gcc: xtensa: Backport patches from upstream/master (v2)

See #29 and #36.

List of patches added after #29:

75ab2f0ebd3c6ab678fea03906186068b89f9fbc "xtensa: Apply a few minor fixes"
46880cd8be7c307f147a8785ac8f58e04a35d34e "xtensa: Fix RTL insn cost estimation about relaxed MOVI instructions"
ec532b47f1823e71f822c0da781c531ffff67a52 "xtensa: Fix buffer overflow"
773dffc50fbc768e3282455bd4238a67b1481176 "xtensa: Optimize integer constant addition that is between -32896 and 32639"
46dc26fdfbf3e64f82188e21aa6a13ec23108e8e "Improve initialization of objects when the initializer has trailing zeros."
e85c94d1c83072d7b894e44009e876dd41ff778a "xtensa: Minor fix for FP constant synthesis"
1884f8978237b15013576a720bcb32e7c5647574 "xtensa: constantsynth: Make try to find shorter instruction"
d6d8e6a7e1379f9dfdf2f39efcc82d9185cca6d0 "xtensa: Optimize "bitwise AND with imm1" followed by "branch if (not) equal to imm2""

patches/gcc10.1/gcc-Improve-initialization-of-objects-when-the-initializ.patch

@@ -0,0 +1,39 @@
+From a2cde0c6443c440c2a2b72b5eea060229a0cff57 Mon Sep 17 00:00:00 2001
+From: Jeff Law <[email protected]>
+Date: Sat, 9 Jul 2022 11:11:00 -0400
+Subject: [PATCH] [RFA] Improve initialization of objects when the initializer
+
+gcc/
+
+	* expr.c (store_expr): Identify trailing NULs in a STRING_CST
+	initializer and use clear_storage rather than copying the
+	NULs to the destination array.
+---
+ gcc/expr.c | 11 +++++++++++
+ 1 file changed, 11 insertions(+)
+
+diff --git a/gcc/expr.c b/gcc/expr.c
+index 991b26f33..6ff393462 100644
+--- a/gcc/expr.c
++++ b/gcc/expr.c
+@@ -5723,6 +5723,17 @@ store_expr (tree exp, rtx target, int call_param_p,
+ 	}
+
+       str_copy_len = TREE_STRING_LENGTH (str);
++
++      /* Trailing NUL bytes in EXP will be handled by the call to
++	 clear_storage, which is more efficient than copying them from
++	 the STRING_CST, so trim those from STR_COPY_LEN.  */
++      while (str_copy_len)
++	{
++	  if (TREE_STRING_POINTER (str)[str_copy_len - 1])
++	    break;
++	  str_copy_len--;
++	}
++
+       if ((STORE_MAX_PIECES & (STORE_MAX_PIECES - 1)) == 0)
+ 	{
+ 	  str_copy_len += STORE_MAX_PIECES - 1;
+-- 
+2.20.1
+

patches/gcc10.1/gcc-xtensa-0006-Fix-non-robust-split-condition-in-define_insn.patch

@@ -0,0 +1,44 @@
+From 2065a3fccb11e28ebcc42aa46c52a40b0fae9bea Mon Sep 17 00:00:00 2001
+From: Kewen Lin <[email protected]>
+Date: Sun, 21 Nov 2021 20:18:31 -0600
+Subject: [PATCH 01/31] xtensa: Fix non-robust split condition in
+ define_insn_and_split
+
+This patch is to fix some non-robust split conditions in some
+define_insn_and_splits, to make each of them applied on top of
+the corresponding condition for define_insn part, otherwise the
+splitting could perform unexpectedly.
+
+gcc/ChangeLog:
+
+	* config/xtensa/xtensa.md (movdi_internal, movdf_internal): Fix split
+	condition.
+---
+ gcc/config/xtensa/xtensa.md | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
+index 2a8e59ee9..123916957 100644
+--- a/gcc/config/xtensa/xtensa.md
++++ b/gcc/config/xtensa/xtensa.md
+@@ -782,7 +782,7 @@
+   "register_operand (operands[0], DImode)
+    || register_operand (operands[1], DImode)"
+   "#"
+-  "reload_completed"
++  "&& reload_completed"
+   [(set (match_dup 0) (match_dup 2))
+    (set (match_dup 1) (match_dup 3))]
+ {
+@@ -1058,7 +1058,7 @@
+   "register_operand (operands[0], DFmode)
+    || register_operand (operands[1], DFmode)"
+   "#"
+-  "reload_completed"
++  "&& reload_completed"
+   [(set (match_dup 0) (match_dup 2))
+    (set (match_dup 1) (match_dup 3))]
+ {
+-- 
+2.20.1
+