From: YunQiang Su <syq@gcc.gnu.org>
Date: Fri, 15 Mar 2024 06:33:58 +0000 (+0800)
Subject: MIPS: Add -m(no-)strict-align option
X-Git-Tag: basepoints/gcc-15~651
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=acc38ff59976e972ba4b1e39f7653813a05de588;p=thirdparty%2Fgcc.git

MIPS: Add -m(no-)strict-align option

We support options -m(no-)unaligned-access 2 years ago, while
currently most of other ports prefer -m(no-)strict-align.
Let's support -m(no-)strict-align, and keep -m(no-)unaligned-access
as alias.

gcc
	* config/mips/mips.opt: Support -mstrict-align, and use
	TARGET_STRICT_ALIGN as the flag; keep -m(no-)unaligned-access
	as alias.
	* config/mips/mips.h: Use TARGET_STRICT_ALIGN.
	* config/mips/mips.opt.urls: Regenerate.
	* doc/invoke.texi: Document -m(no-)strict-algin for MIPSr6.
---

diff --git a/gcc/config/mips/mips.h b/gcc/config/mips/mips.h
index 7145d23c6508..6444a68dfd58 100644
--- a/gcc/config/mips/mips.h
+++ b/gcc/config/mips/mips.h
@@ -251,7 +251,7 @@ struct mips_cpu_info {
 				     || ISA_HAS_MSA))
 
 /* ISA load/store instructions can handle unaligned address */
-#define ISA_HAS_UNALIGNED_ACCESS (TARGET_UNALIGNED_ACCESS \
+#define ISA_HAS_UNALIGNED_ACCESS (!TARGET_STRICT_ALIGN \
 				 && (mips_isa_rev >= 6))
 
 /* The ISA compression flags that are currently in effect.  */
diff --git a/gcc/config/mips/mips.opt b/gcc/config/mips/mips.opt
index ce36942aabe6..c1abb36212f9 100644
--- a/gcc/config/mips/mips.opt
+++ b/gcc/config/mips/mips.opt
@@ -429,9 +429,17 @@ mtune=
 Target RejectNegative Joined Var(mips_tune_option) ToLower Enum(mips_arch_opt_value)
 -mtune=PROCESSOR	Optimize the output for PROCESSOR.
 
+mstrict-align
+Target Var(TARGET_STRICT_ALIGN) Init(0)
+Don't generate code with unaligned load store, only valid for MIPS R6.
+
 munaligned-access
-Target Var(TARGET_UNALIGNED_ACCESS) Init(1)
-Generate code with unaligned load store, valid for MIPS R6.
+Target RejectNegative Alias(mstrict-align) NegativeAlias
+Generate code with unaligned load store for R6 (alias of -mno-strict-align).
+
+mno-unaligned-access
+Target RejectNegative Alias(mstrict-align)
+Don't generate code with unaligned load store for R6 (alias of -mstrict-align).
 
 muninit-const-in-rodata
 Target Var(TARGET_UNINIT_CONST_IN_RODATA)
diff --git a/gcc/config/mips/mips.opt.urls b/gcc/config/mips/mips.opt.urls
index 96aba041026a..9d166646d65c 100644
--- a/gcc/config/mips/mips.opt.urls
+++ b/gcc/config/mips/mips.opt.urls
@@ -233,9 +233,15 @@ UrlSuffix(gcc/MIPS-Options.html#index-mmadd4)
 mtune=
 UrlSuffix(gcc/MIPS-Options.html#index-mtune-10)
 
+mstrict-align
+UrlSuffix(gcc/MIPS-Options.html#index-mstrict-align-3)
+
 munaligned-access
 UrlSuffix(gcc/MIPS-Options.html#index-munaligned-access-1)
 
+mno-unaligned-access
+UrlSuffix(gcc/MIPS-Options.html#index-mno-unaligned-access-1)
+
 muninit-const-in-rodata
 UrlSuffix(gcc/MIPS-Options.html#index-muninit-const-in-rodata)
 
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 85c938d4a148..864768fd2f42 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -1143,7 +1143,8 @@ Objective-C and Objective-C++ Dialects}.
 -mcheck-zero-division  -mno-check-zero-division
 -mdivide-traps  -mdivide-breaks
 -mload-store-pairs  -mno-load-store-pairs
--munaligned-access  -mno-unaligned-access
+-mstrict-align  -mno-strict-align
+-mno-unaligned-access  -munaligned-access
 -mmemcpy  -mno-memcpy  -mlong-calls  -mno-long-calls
 -mmad  -mno-mad  -mimadd  -mno-imadd  -mfused-madd  -mno-fused-madd  -nocpp
 -mfix-24k  -mno-fix-24k
@@ -28561,14 +28562,19 @@ instructions to enable load/store bonding.  This option is enabled by
 default but only takes effect when the selected architecture is known
 to support bonding.
 
+@opindex mstrict-align
+@opindex mno-strict-align
 @opindex munaligned-access
 @opindex mno-unaligned-access
-@item -munaligned-access
+@item -mstrict-align
+@itemx -mno-strict-align
+@itemx -munaligned-access
 @itemx -mno-unaligned-access
-Enable (disable) direct unaligned access for MIPS Release 6.
-MIPSr6 requires load/store unaligned-access support,
-by hardware or trap&emulate.
-So @option{-mno-unaligned-access} may be needed by kernel.
+Disable (enable) direct unaligned access for MIPS Release 6.
+MIPSr6 requires load/store unaligned-access support, by hardware or
+trap&emulate.  So @option{-mstrict-align} may be needed by kernel.  The
+options @option{-munaligned-access} and @option{-mno-unaligned-access}
+are obsoleted, and only for backward-compatible.
 
 @opindex mmemcpy
 @opindex mno-memcpy