[gcc(refs/vendors/ibm/heads/perf)] re PR tree-optimization/90883 (Generated code is worse if returned struct is unnamed)

[Jiu Fu Guo]

https://gcc.gnu.org/g:46275300312b44e1388b86a45f1600a5a1722303

commit 46275300312b44e1388b86a45f1600a5a1722303
Author: Kito Cheng <kito.cheng@sifive.com>
Date:   Tue Mar 3 14:16:42 2020 +0800

    re PR tree-optimization/90883 (Generated code is worse if returned struct is unnamed)
    
    After add --param max-inline-insns-size=1 all target will remove the
    redundant store at dse1, except some targets like AArch64 and MIPS will
    expand the struct initialization into loop due to CLEAR_RATIO.
    
    Tested on cross compiler of riscv32, riscv64, x86, x86_64, mips, mips64,
    aarch64, nds32 and arm.
    
    gcc/testsuite/ChangeLog
    
            PR tree-optimization/90883
            * g++.dg/tree-ssa/pr90883.c: Add --param max-inline-insns-size=1.
            Add aarch64-*-* mips*-*-* to XFAIL.

Diff:
---
 gcc/testsuite/ChangeLog                 | 6 ++++++
 gcc/testsuite/g++.dg/tree-ssa/pr90883.C | 6 +++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6b4f301bb39..6b8b5c03c4d 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-06  Kito Cheng  <kito.cheng@sifive.com>
+
+	PR tree-optimization/90883
+	* g++.dg/tree-ssa/pr90883.c: Add --param max-inline-insns-size=1.
+	Add aarch64-*-* mips*-*-* to XFAIL.
+
 2020-03-05  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/89229
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr90883.C b/gcc/testsuite/g++.dg/tree-ssa/pr90883.C
index c5faffa1f32..0e622f263d2 100644
--- a/gcc/testsuite/g++.dg/tree-ssa/pr90883.C
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr90883.C
@@ -1,4 +1,4 @@
-// { dg-options "-O2 -Os -fdump-tree-dse-details -std=c++11" }
+// { dg-options "-O2 -Os -fdump-tree-dse-details -std=c++11 --param max-inline-insns-size=1" }
 
 
     class C
@@ -15,6 +15,6 @@
 
 // We want to match enough here to capture that we deleted an empty
 // constructor store
-// { dg-final { scan-tree-dump "Deleted redundant store: .*\.a = {}" "dse1" { target { ! i?86-*-* } } } }
-// { dg-final { scan-tree-dump "Deleted redundant store: .*\.a = {}" "dse2" { target i?86-*-* } } }
+// aarch64 and mips will expand to loop to clear because CLEAR_RATIO.
+// { dg-final { scan-tree-dump "Deleted redundant store: .*\.a = {}" "dse1" { xfail { aarch64-*-* mips*-*-* } } } }