arm: Fix PCS for SFmode -> SImode libcalls [PR99748]

Message ID 20210401161113.3eztd7en7eku4a32@arm.com
State New
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Series
  • arm: Fix PCS for SFmode -> SImode libcalls [PR99748]
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Commit Message

Paul Richard Thomas via Gcc-patches April 1, 2021, 4:11 p.m.
Hi all,

This patch fixes PR99748 which shows us trying to pass the argument to
__aeabi_f2iz in the VFP register s0 when the library function is
expecting to use the GPR r0. It also fixes the __aeabi_f2uiz case which
was broken in the same way.

For the testcase in the PR, here is the code we generate before the
patch (with -mfloat-abi=hard -march=armv8.1-m.main+mve -O0):

main:
    push    {r7, lr}
    sub     sp, sp, #8
    add     r7, sp, #0
    mov     r3, #1065353216
    str     r3, [r7, #4]    @ float
    vldr.32 s0, [r7, #4]
    bl      __aeabi_f2iz
    mov     r3, r0
    cmp     r3, #1
    [...]

This becomes:

main:
    push    {r7, lr}
    sub     sp, sp, #8
    add     r7, sp, #0
    mov     r3, #1065353216
    str     r3, [r7, #4]    @ float
    ldr     r0, [r7, #4]    @ float
    bl      __aeabi_f2iz
    mov     r3, r0
    cmp     r3, #1
    [...]

after the patch. We see a similar change for the same testcase with a
cast to unsigned instead of int.

Testing:
 * Bootstrapped and regtested on arm-linux-gnueabihf, no regressions.
 * Regtested an arm-eabi cross configured with --with-float=hard
   --with-arch=armv8.1-m.main+mve. This shows that the patch fixes the
   following execution failures:

   FAIL->PASS: gcc.c-torture/execute/20000605-1.c   -O0  execution test
   FAIL->PASS: gcc.c-torture/execute/conversion.c   -O0  execution test
   FAIL->PASS: gcc.c-torture/execute/float-floor.c   -O0  execution test
   FAIL->PASS: gcc.c-torture/execute/float-floor.c   -O1  execution test
   FAIL->PASS: gcc.c-torture/execute/float-floor.c   -O2  execution test
   FAIL->PASS: gcc.c-torture/execute/float-floor.c   -O2 -flto -fno-use-linker-plugin -flto-partition=none  execution test
   FAIL->PASS: gcc.c-torture/execute/float-floor.c   -O3 -g  execution test
   FAIL->PASS: gcc.c-torture/execute/float-floor.c   -Os  execution test
   FAIL->PASS: gcc.c-torture/execute/gofast.c   -O0  execution test
   FAIL->PASS: gcc.dg/torture/float32-basic.c   -O0  execution test
   FAIL->PASS: gcc.dg/torture/float32-basic.c   -O1  execution test
   FAIL->PASS: gcc.dg/torture/float32-basic.c   -O2  execution test
   FAIL->PASS: gcc.dg/torture/float32-basic.c   -O2 -flto -fno-use-linker-plugin -flto-partition=none  execution test
   FAIL->PASS: gcc.dg/torture/float32-basic.c   -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects  execution test
   FAIL->PASS: gcc.dg/torture/float32-basic.c   -O3 -g  execution test
   FAIL->PASS: gcc.dg/torture/float32-basic.c   -Os  execution test

OK for trunk?

Thanks,
Alex

gcc/ChangeLog:

	* config/arm/arm.c (arm_libcall_uses_aapcs_base): Also use base
	PCS for [su]fix_optab.

Comments

Paul Richard Thomas via Gcc-patches April 1, 2021, 5:35 p.m. | #1
On 01/04/2021 17:11, Alex Coplan via Gcc-patches wrote:
> Hi all,

> 

> This patch fixes PR99748 which shows us trying to pass the argument to

> __aeabi_f2iz in the VFP register s0 when the library function is

> expecting to use the GPR r0. It also fixes the __aeabi_f2uiz case which

> was broken in the same way.

> 

> For the testcase in the PR, here is the code we generate before the

> patch (with -mfloat-abi=hard -march=armv8.1-m.main+mve -O0):

> 

> main:

>      push    {r7, lr}

>      sub     sp, sp, #8

>      add     r7, sp, #0

>      mov     r3, #1065353216

>      str     r3, [r7, #4]    @ float

>      vldr.32 s0, [r7, #4]

>      bl      __aeabi_f2iz

>      mov     r3, r0

>      cmp     r3, #1

>      [...]

> 

> This becomes:

> 

> main:

>      push    {r7, lr}

>      sub     sp, sp, #8

>      add     r7, sp, #0

>      mov     r3, #1065353216

>      str     r3, [r7, #4]    @ float

>      ldr     r0, [r7, #4]    @ float

>      bl      __aeabi_f2iz

>      mov     r3, r0

>      cmp     r3, #1

>      [...]

> 

> after the patch. We see a similar change for the same testcase with a

> cast to unsigned instead of int.

> 

> Testing:

>   * Bootstrapped and regtested on arm-linux-gnueabihf, no regressions.

>   * Regtested an arm-eabi cross configured with --with-float=hard

>     --with-arch=armv8.1-m.main+mve. This shows that the patch fixes the

>     following execution failures:

> 

>     FAIL->PASS: gcc.c-torture/execute/20000605-1.c   -O0  execution test

>     FAIL->PASS: gcc.c-torture/execute/conversion.c   -O0  execution test

>     FAIL->PASS: gcc.c-torture/execute/float-floor.c   -O0  execution test

>     FAIL->PASS: gcc.c-torture/execute/float-floor.c   -O1  execution test

>     FAIL->PASS: gcc.c-torture/execute/float-floor.c   -O2  execution test

>     FAIL->PASS: gcc.c-torture/execute/float-floor.c   -O2 -flto -fno-use-linker-plugin -flto-partition=none  execution test

>     FAIL->PASS: gcc.c-torture/execute/float-floor.c   -O3 -g  execution test

>     FAIL->PASS: gcc.c-torture/execute/float-floor.c   -Os  execution test

>     FAIL->PASS: gcc.c-torture/execute/gofast.c   -O0  execution test

>     FAIL->PASS: gcc.dg/torture/float32-basic.c   -O0  execution test

>     FAIL->PASS: gcc.dg/torture/float32-basic.c   -O1  execution test

>     FAIL->PASS: gcc.dg/torture/float32-basic.c   -O2  execution test

>     FAIL->PASS: gcc.dg/torture/float32-basic.c   -O2 -flto -fno-use-linker-plugin -flto-partition=none  execution test

>     FAIL->PASS: gcc.dg/torture/float32-basic.c   -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects  execution test

>     FAIL->PASS: gcc.dg/torture/float32-basic.c   -O3 -g  execution test

>     FAIL->PASS: gcc.dg/torture/float32-basic.c   -Os  execution test

> 

> OK for trunk?

> 

> Thanks,

> Alex

> 

> gcc/ChangeLog:

> 

> 	* config/arm/arm.c (arm_libcall_uses_aapcs_base): Also use base

> 	PCS for [su]fix_optab.

> 


OK.

As a wrong code bug we should probably be looking to backport this if 
needed (though it's likely too late now for 10.3).

R.

Patch

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 518bfed1c35..8910dad8214 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -5773,6 +5773,10 @@  arm_libcall_uses_aapcs_base (const_rtx libcall)
 		   convert_optab_libfunc (sfix_optab, DImode, SFmode));
       add_libcall (libcall_htab,
 		   convert_optab_libfunc (ufix_optab, DImode, SFmode));
+      add_libcall (libcall_htab,
+		   convert_optab_libfunc (sfix_optab, SImode, SFmode));
+      add_libcall (libcall_htab,
+		   convert_optab_libfunc (ufix_optab, SImode, SFmode));
 
       /* Values from double-precision helper functions are returned in core
 	 registers if the selected core only supports single-precision