[Bug target/38900] ICE: unable to find a register to spill

[ktietz at gcc dot gnu dot org]

------- Comment #15 from ktietz at gcc dot gnu dot org  2009-07-06 17:02 -------
(In reply to comment #14)
> > By simply re-ording of arguments fos sibcall_1 and sibcall_value_1, so that c
> > is last element, produced code is ok and no ICE I've seen.
> 
> Disparaging it ("s,!c,d,a") would be even more robust I think.
> 

yeah, this works, too. But the d needs the !, too. As when I alter my testcase
by giving the dllimport'ed fastcall a second argument, it ICEs again.

$ /usr/local/bin/i686-pc-mingw32-gcc.exe -o t.s -S c_impfast2.c -O2
c_impfast2.c: In function 'f':
c_impfast2.c:7:1: error: unable to find a register to spill in class 'DREG'
c_impfast2.c:7:1: error: this is the insn:
(call_insn/j 12 10 13 2 c_impfast2.c:6 (call (mem:QI (reg/f:SI 3 bx [58]) [0 S1
A8])
        (const_int 0 [0x0])) 462 {*sibcall_1} (expr_list:REG_DEAD (reg/f:SI 3
bx [58])
        (expr_list:REG_DEAD (reg:SI 2 cx)
            (expr_list:REG_DEAD (reg:SI 1 dx)
                (nil))))
    (expr_list:REG_DEP_TRUE (use (reg:SI 2 cx))
        (expr_list:REG_DEP_TRUE (use (reg:SI 1 dx))
            (nil))))
c_impfast2.c:7:1: internal compiler error: in spill_failure, at reload1.c:2094
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

So with both c and d changed to !c and !d for sibcall_1 and sibcall_value_1 it
translates without ICE to:

        .file   "c_impfast2.c"
        .text
        .p2align 4,,15
.globl _f
        .def    _f;     .scl    2;      .type   32;     .endef
_f:
        pushl   %ebp
        movl    $1, %edx
        movl    %esp, %ebp
        movl    $2, %ecx
        pushl   %ebx
        subl    $4, %esp
        movl    __imp_@h@8, %ebx
        call    *%ebx
        addl    $4, %esp
        movl    $2, %edx
        movl    $1, %ecx
        movl    %ebx, %eax
        popl    %ebx
        popl    %ebp
        jmp     *%eax

New patch for i386.md (and you are right the !c,!d is more robust here) is:

Index: gcc/gcc/config/i386/i386.md
===================================================================
--- gcc.orig/gcc/config/i386/i386.md    2009-07-06 18:14:36.155670000 +0200
+++ gcc/gcc/config/i386/i386.md 2009-07-06 18:53:10.459670100 +0200
@@ -15536,7 +15536,7 @@
   [(set_attr "type" "call")])

 (define_insn "*sibcall_1"
-  [(call (mem:QI (match_operand:SI 0 "sibcall_insn_operand" "s,c,d,a"))
+  [(call (mem:QI (match_operand:SI 0 "sibcall_insn_operand" "s,!c,!d,a"))
         (match_operand 1 "" ""))]
   "SIBLING_CALL_P (insn) && !TARGET_64BIT"
 {
@@ -22183,7 +22183,7 @@

 (define_insn "*sibcall_value_1"
   [(set (match_operand 0 "" "")
-       (call (mem:QI (match_operand:SI 1 "sibcall_insn_operand" "s,c,d,a"))
+       (call (mem:QI (match_operand:SI 1 "sibcall_insn_operand" "s,!c,!d,a"))
              (match_operand:SI 2 "" "")))]
   "SIBLING_CALL_P (insn) && !TARGET_64BIT"
 {


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38900