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

[Alex Coplan via Gcc-patches]

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.

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