From: Alex Coplan <alex.coplan@arm.com>
Date: Tue, 6 Apr 2021 08:06:27 +0000 (+0100)
Subject: arm: Fix PCS for SFmode -> SImode libcalls [PR99748]
X-Git-Tag: basepoints/gcc-12~258
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=16ea7f57891d3fe885ee55b2917208695e184714;p=thirdparty%2Fgcc.git

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

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.

gcc/ChangeLog:

	PR target/99748
	* 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 518bfed1c35c..8910dad82146 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