[COMMITTED] Turn of ipa-ra in builtins test (PR91059)

[COMMITTED] Turn of ipa-ra in builtins test (PR91059)

[Wilco Dijkstra]

The gcc.c-torture/execute/builtins/lib directory contains a reimplementation
of many C library string functions, which causes non-trivial register allocation
bugs with LTO and static linked libraries.  To fix this long-standing test issue,
turn off ipa-ra which avoids the register corruption across calls.  All builtin
torture tests now pass on aarch64-none-elf.  Committed as obvious.

ChangeLog:
2019-07-08  Wilco Dijkstra  <wdijkstr@arm.com>

testsuite/
	PR testsuite/91059
	PR testsuite/78529
	* gcc.c-torture/execute/builtins/builtins.exp: Add -fno-ipa-ra.
--

diff --git a/gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp b/gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp
index fb9d3ece181fee3489e1ddd2f72f40dbbf807bb6..d62f78c7a6c52c3adea5e4c216f12765acadf60e 100644
--- a/gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp
+++ b/gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp
@@ -37,7 +37,7 @@ load_lib c-torture.exp
 torture-init
 set-torture-options $C_TORTURE_OPTIONS {{}} $LTO_TORTURE_OPTIONS
 
-set additional_flags "-fno-tree-dse -fno-tree-loop-distribute-patterns -fno-tracer"
+set additional_flags "-fno-tree-dse -fno-tree-loop-distribute-patterns -fno-tracer -fno-ipa-ra"
 if [istarget "powerpc-*-darwin*"] {
    lappend additional_flags "-Wl,-multiply_defined,suppress"
 }

Re: [COMMITTED] Turn of ipa-ra in builtins test (PR91059)

[Alexander Monakov]

On Mon, 8 Jul 2019, Wilco Dijkstra wrote:

> The gcc.c-torture/execute/builtins/lib directory contains a reimplementation
> of many C library string functions, which causes non-trivial register allocation
> bugs with LTO and static linked libraries.  To fix this long-standing test issue,
> turn off ipa-ra which avoids the register corruption across calls.  All builtin
> torture tests now pass on aarch64-none-elf.  Committed as obvious.

Would have been nice if the above text also mentioned that PR 78527 has some
background info for the "obvious".  The paragraph went into commit text, but on
its own it doesn't explain what's "obvious" here at all :(

(went looking for the explanation after collecting jaw from the floor; I don't
agree with triage shown there, but what does it matter...)

> ChangeLog:
> 2019-07-08  Wilco Dijkstra  <wdijkstr@arm.com>
> 
> testsuite/
> 	PR testsuite/91059
> 	PR testsuite/78529
> 	* gcc.c-torture/execute/builtins/builtins.exp: Add -fno-ipa-ra.

Alexander

Re: [COMMITTED] Turn of ipa-ra in builtins test (PR91059)

[Wilco Dijkstra]

Hi Alexander,
 
> Would have been nice if the above text also mentioned that PR 78527 has some
> background info for the "obvious".  The paragraph went into commit text, but on
> its own it doesn't explain what's "obvious" here at all :(
 
The "obvious" refers to the patch itself under the commit rules. The issue itself is 
non-obvious of course.

> (went looking for the explanation after collecting jaw from the floor; I don't
> agree with triage shown there, but what does it matter...)

Yes, it was a huge waste of time before the underlying cause was found (comment #26).
Worse, absolutely nothing happened after all that...

Wilco

Re: [COMMITTED] Turn of ipa-ra in builtins test (PR91059)

[Wilco Dijkstra]

Hi,

I've now backported this to all active branches so the issue can no
longer occur:

Turn off ipa-ra in builtins test (PR91059)

The gcc.c-torture/execute/builtins/lib directory contains a reimplementation
of many C library string functions, which causes non-trivial register allocation
bugs with LTO and static linked libraries.  To fix this long-standing test issue,
turn off ipa-ra which avoids the register corruption across calls.  All builtin
torture tests now pass on aarch64-none-elf.  Committed as obvious.
See PR78529 for more details.

ChangeLog:
2019-07-12  Wilco Dijkstra  <wdijkstr@arm.com>

testsuite/
        PR testsuite/78529
        * gcc.c-torture/execute/builtins/builtins.exp: Add -fno-ipa-ra.
--

diff --git a/gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp b/gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp
index fb9d3ece181fee3489e1ddd2f72f40dbbf807bb6..d62f78c7a6c52c3adea5e4c216f12765acadf60e 100644
--- a/gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp
+++ b/gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp
@@ -37,7 +37,7 @@ load_lib c-torture.exp
 torture-init
 set-torture-options $C_TORTURE_OPTIONS {{}} $LTO_TORTURE_OPTIONS
 
-set additional_flags "-fno-tree-dse -fno-tree-loop-distribute-patterns -fno-tracer"
+set additional_flags "-fno-tree-dse -fno-tree-loop-distribute-patterns -fno-tracer -fno-ipa-ra"
 if [istarget "powerpc-*-darwin*"] {
    lappend additional_flags "-Wl,-multiply_defined,suppress"
 }