http://gcc.gnu.org/ml/gcc-patches/2011-07/msg01036.html
Georg-Johann Lay wrote:
> This is a patch to fix PR49487.
Forgot to attach it. Here it is.
> As Denis will be off-line for some time, it'd be great if
> a global reviewer would review it. It appears that he is
> the only AVR maintainer who approves patches.
>
> The reason for the ICE is as explained in the PR:
>
> Rotate pattern use "X" as constraint for an operand which is
> used as scratch. However, the operand is a match_operand
> and not a match_scratch.
>
> Because the scratch is not needed in all situations, I choose
> to use match_scratch instead of match_operand and not to fix
> the constraints. Fixing constraints would lead to superfluous
> allocation of register if no scratch was needed.
>
> Tested with 2 FAILs less: gcc.c-torture/compile/pr46883.c
> ICEs without this patch and passes with it.
>
> The test case in the PR passes, too. That test case
> passes also the current unpatched 4.7, but it's obvious that
> the constraint/operand combination is a bug.
>
> Ok to commit and back-port to 4.6?
>
> Johann
>
> PR target/49487
> * config/avr/avr.md (rotl<mode>3): Generate SCRATCH instead
> of REG.
> (*rotw<mode>): Use const_int_operand for operands2.
> Use match_scatch for operands3.
> (*rotb<mode>): Ditto
> * config/avr/avr.c (avr_rotate_bytes): Treat SCRATCH.
Index: config/avr/avr.md
===================================================================
--- config/avr/avr.md (revision 176136)
+++ config/avr/avr.md (working copy)
@@ -1597,18 +1597,18 @@ (define_expand "rotl<mode>3"
(match_operand:VOID 2 "const_int_operand" "")))
(clobber (match_dup 3))])]
""
- "
-{
- if (CONST_INT_P (operands[2]) && 0 == (INTVAL (operands[2]) % 8))
{
- if (AVR_HAVE_MOVW && 0 == INTVAL (operands[2]) % 16)
- operands[3] = gen_reg_rtx (<rotsmode>mode);
- else
- operands[3] = gen_reg_rtx (QImode);
- }
- else
- FAIL;
-}")
+ if (CONST_INT_P (operands[2])
+ && 0 == INTVAL (operands[2]) % 8)
+ {
+ if (AVR_HAVE_MOVW && 0 == INTVAL (operands[2]) % 16)
+ operands[3] = gen_rtx_SCRATCH (<rotsmode>mode);
+ else
+ operands[3] = gen_rtx_SCRATCH (QImode);
+ }
+ else
+ FAIL;
+ })
;; Overlapping non-HImode registers often (but not always) need a scratch.
@@ -1620,34 +1620,38 @@ (define_expand "rotl<mode>3"
; Split word aligned rotates using scratch that is mode dependent.
(define_insn_and_split "*rotw<mode>"
[(set (match_operand:HIDI 0 "register_operand" "=r,r,#&r")
- (rotate:HIDI (match_operand:HIDI 1 "register_operand" "0,r,r")
- (match_operand 2 "immediate_operand" "n,n,n")))
- (clobber (match_operand:<rotsmode> 3 "register_operand" "=<rotx>" ))]
- "(CONST_INT_P (operands[2]) &&
- (0 == (INTVAL (operands[2]) % 16) && AVR_HAVE_MOVW))"
+ (rotate:HIDI (match_operand:HIDI 1 "register_operand" "0,r,r")
+ (match_operand 2 "const_int_operand" "n,n,n")))
+ (clobber (match_scratch:<rotsmode> 3 "=<rotx>"))]
+ "AVR_HAVE_MOVW
+ && CONST_INT_P (operands[2])
+ && 0 == INTVAL (operands[2]) % 16"
"#"
"&& (reload_completed || <MODE>mode == DImode)"
[(const_int 0)]
- "avr_rotate_bytes (operands);
- DONE;"
-)
+ {
+ avr_rotate_bytes (operands);
+ DONE;
+ })
; Split byte aligned rotates using scratch that is always QI mode.
(define_insn_and_split "*rotb<mode>"
[(set (match_operand:HIDI 0 "register_operand" "=r,r,#&r")
- (rotate:HIDI (match_operand:HIDI 1 "register_operand" "0,r,r")
- (match_operand 2 "immediate_operand" "n,n,n")))
- (clobber (match_operand:QI 3 "register_operand" "=<rotx>" ))]
- "(CONST_INT_P (operands[2]) &&
- (8 == (INTVAL (operands[2]) % 16)
- || (!AVR_HAVE_MOVW && 0 == (INTVAL (operands[2]) % 16))))"
+ (rotate:HIDI (match_operand:HIDI 1 "register_operand" "0,r,r")
+ (match_operand 2 "const_int_operand" "n,n,n")))
+ (clobber (match_scratch:QI 3 "=<rotx>"))]
+ "CONST_INT_P (operands[2])
+ && (8 == INTVAL (operands[2]) % 16
+ || (!AVR_HAVE_MOVW
+ && 0 == INTVAL (operands[2]) % 16))"
"#"
"&& (reload_completed || <MODE>mode == DImode)"
[(const_int 0)]
- "avr_rotate_bytes (operands);
- DONE;"
-)
+ {
+ avr_rotate_bytes (operands);
+ DONE;
+ })
;;<< << << << << << << << << << << << << << << << << << << << << << << << << <<
Index: config/avr/avr.c
===================================================================
--- config/avr/avr.c (revision 176141)
+++ config/avr/avr.c (working copy)
@@ -4438,7 +4438,9 @@ avr_rotate_bytes (rtx operands[])
if (mode == DImode)
move_mode = QImode;
/* Make scratch smaller if needed. */
- if (GET_MODE (scratch) == HImode && move_mode == QImode)
+ if (SCRATCH != GET_CODE (scratch)
+ && HImode == GET_MODE (scratch)
+ && QImode == move_mode)
scratch = simplify_gen_subreg (move_mode, scratch, HImode, 0);
move_size = GET_MODE_SIZE (move_mode);
@@ -4534,6 +4536,8 @@ avr_rotate_bytes (rtx operands[])
When this move occurs, it will break chain deadlock.
The scratch register is substituted for real move. */
+ gcc_assert (SCRATCH != GET_CODE (scratch));
+
move[size].src = move[blocked].dst;
move[size].dst = scratch;
/* Scratch move is never blocked. */
