[gcc(refs/users/meissner/heads/work122)] Update ChangeLog.meissner

[Michael Meissner]

https://gcc.gnu.org/g:415f216b7a5559f3cb6eed910820e6be9da5cd15

commit 415f216b7a5559f3cb6eed910820e6be9da5cd15
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Wed Jun 7 14:57:56 2023 -0400

    Update ChangeLog.meissner

Diff:
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 gcc/ChangeLog.meissner | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/gcc/ChangeLog.meissner b/gcc/ChangeLog.meissner
index 108f9865e9e..98e7004b034 100644
--- a/gcc/ChangeLog.meissner
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@@ -1,3 +1,56 @@
+==================== Branch work122, patch #1 ====================
+
+Fix power10 fusion and -fstack-protector, PR target/105325
+
+This patch fixes an issue where if you use the -fstack-protector and
+-mcpu=power10 options and you have a large stack frame, the GCC compiler will
+generate a LWA instruction with a large offset.
+
+There are several problems:
+
+    1)	The prefixed attribute was not checking insns with the type
+	fused_load_cmpi for being load insns.
+
+    2)	The recognition of LWA for being prefixed looks at the "sign_extend"
+	attribute and whether the register mode was different than the memory
+	load (i.e. does it have a sign_extend wrapper around the load).
+
+    3)	The constraints in fusion.md (generated by genfusion.pl) use "m" for LWA
+	and LD, when they should use "YZ".
+
+    4)	There is a lwa_operand that should be used instead of
+	ds_form_mem_operand for the LWA instruction.
+
+The main fix is to modify genfusion.pl that it sets the appropriate predicates
+and constraints.
+
+I also added support in genfusion.md so that if we are doing a LWA operation and
+just setting the CC bits (throwing away the result of the load after the
+comparison), it generates a LWZ instruction and does a CMPWI instead of CMPDI.
+This way those loads can use normal D-FORM restrictions instead of DS-form.
+
+I set the "sign_extend" attribute on the cases that generate LWA.
+
+I modified the "prefixed" attribute so that it also checks fused_load_cmpi.
+
+2023-06-06   Michael Meissner  <meissner@linux.ibm.com>
+
+gcc/
+
+	* config/rs6000/genfusion.pl (gen_ld_cmpi_p10_one): Fix constraints and
+	predicates for LD and LWA.  Optimize LWA/CMPDI to generate LWZ/CMPWI if
+	we don't need the result of the load after the comparison.  Change the
+	name of the insn pattern to reflect whether a DImode or SImode register
+	is loaded.  Set sign_extend attribute for LWA instruction.
+	* config/rs6000/fusion.md: Regenerate.
+	* config/rs6000/rs6000.md (prefixed attribute): Treat fused_load_cmpi
+	insns as being load insns.
+
+gcc/testsuite/
+
+	* g++.target/powerpc/pr105325.C: New test.
+
+
 ==================== Branch work122, baseline ====================
 
 2023-06-06   Michael Meissner  <meissner@linux.ibm.com>