Gentle ping 🙂
Kind regards,
Torbjörn
On 2024-12-18 11:46, Torbjorn SVENSSON wrote:
On 2024-12-12 15:50, Richard Earnshaw (lists) wrote:
On 12/12/2024 13:36, Torbjorn SVENSSON wrote:
On 2024-12-12 12:26, Richard Earnshaw (lists) wrote:
On 10/11/2024 13:38, Torbjörn SVENSSON wrote:
Hi Richard,
I'm not sure if I'm doing something wrong here, or if it was an
oversight
when doing the update in r12-8108-g62082d278d1.
Anyway, the commit message suggest that it's only the constant that
is of
interrest, so I updated the test to only check the constant. Do you
think
this is enough, or is should the test case also verify that it's
used in
a "set" expression?
Ok for trunk and releases/gcc-14?
--
The test case was re-writtend in r12-8108-g62082d278d1, but the
expected
RTL was not updated.
The diff for the generated reg_equal_test.c.*r.expand files
produced by
r12-8108-g62082d278d1 and r15-5047-g7e1d9f58858 is:
--- reg_equal_test.c.253r.expand-r12-8108-g62082d278d1 2024-11-10
14:24:54.957438394 +0100
+++ reg_equal_test.c.268r.expand-r15-5047-g7e1d9f58858 2024-11-10
14:30:13.633437178 +0100
@@ -1,5 +1,5 @@
-;; Function x (x, funcdef_no=0, decl_uid=4195, cgraph_uid=1,
symbol_order=0)
+;; Function x (x, funcdef_no=0, decl_uid=4590, cgraph_uid=1,
symbol_order=0)
;; Generating RTL for gimple basic block 2
@@ -25,6 +25,6 @@
(note 1 0 3 NOTE_INSN_DELETED)
(note 3 1 2 2 [bb 2] NOTE_INSN_BASIC_BLOCK)
(note 2 3 5 2 NOTE_INSN_FUNCTION_BEG)
-(insn 5 2 0 2 (set (reg/v:SI 113 [ d ])
+(insn 5 2 0 2 (set (reg/v:SI 114 [ d ])
(const_int -942519458 [0xffffffffc7d24b5e])) -1
(nil))
That's not what I see if I compile with "-march=armv8-a -mthumb". I
get the reg_equal note that I expect and the insn is something like:
(insn 6 5 0 2 (set (zero_extract:SI (reg/v:SI 114 [ d ])
(const_int 16 [0x10])
(const_int 16 [0x10]))
(const_int 51154 [0xc7d2])) -1
(expr_list:REG_EQUAL (const_int -942519458 [0xffffffffc7d24b5e])
(nil)))
Can you tell me the exact options you were using to get your output?
Hmm.. This is interesting. With Cortex-A, I do see the same output
that you get. With Cortex-M, it's instead my output.
You can get my output with any of the Cortex-M targets (M3 or above):
This is the line that I've used
arm-none-eabi-gcc gcc.target/arm/reg_equal_test.c -mthumb -
march=armv8.1-m.main -mfloat-abi=soft -fgimple -O1 -fdump-rtl-expand
- S -o /dev/null
I suppose the change I propose will match both cases, but is there
any backside of not checking the REG_EQUAL part?
Should the test case be Cortex-A only?
I don't think so. We'd expect the code to be using MOVW/MOVT here and
that's what the require rules seem to be saying. That constant can't
really be handled by a single mov, so it looks like for your case the
compiler is expecting this value to be spilled to a constant pool
later on. It might be legitimate with some costing models, but it
seems a bit unlikely, especially when not -Os.
So to conclude; There are 2 different outcomes from this.
1. A MOVW and MOVT is generated (at least for armv8-a, maybe other
Cortex-A targets too?)
2. A LDR with a literal pool (at least for Cortex-M)
How can these 2 cases be combined into one test case that will actually
check that the right thing is generated?
For the size check, I'd opt to just remove it.
Kind regards,
Torbjörn
R.
Kind regards,
Torbjörn
R.
In both versions, the constant is simply assigned, thus I updated the
expected RTL accordingly.
gcc/testsuite/ChangeLog:
* gcc.target/arm/reg_equal_test.c: Update expected RTL.
Signed-off-by: Torbjörn SVENSSON <torbjorn.svens...@foss.st.com>
---
gcc/testsuite/gcc.target/arm/reg_equal_test.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/testsuite/gcc.target/arm/reg_equal_test.c b/gcc/
testsuite/gcc.target/arm/reg_equal_test.c
index d87c75cc27c..4337e3f0af5 100644
--- a/gcc/testsuite/gcc.target/arm/reg_equal_test.c
+++ b/gcc/testsuite/gcc.target/arm/reg_equal_test.c
@@ -12,4 +12,4 @@ x ()
return;
}
-/* { dg-final { scan-rtl-dump "expr_list:REG_EQUAL \\(const_int
-942519458" "expand" } } */
+/* { dg-final { scan-rtl-dump "\\(const_int -942519458"
"expand" } } */
