powerpc64 large-toc vs. reload
Alan Modra
amodra@gmail.com
Sun Jun 19 18:15:00 GMT 2011
I was alerted to a problem with large toc (-mcmodel=medium/large) code
a few days ago by warnings emitted during a binutils build.
dwarf.c: In function 'display_debug_lines_raw':
dwarf.c:2409:1: note: non-delegitimized UNSPEC UNSPEC_TOCREL (44) found in variable location
dwarf.c:2409:1: note: non-delegitimized UNSPEC UNSPEC_TOCREL (44) found in variable location
On investigating why this was happening, I found that these UNSPECs
were from the high part calculation of a toc-relative address that
didn't get a register. reload allocated the pseudo to a stack slot..
The stack slot didn't match the tight pattern in delegitimize_address
which is why we have an UNSPEC left in the debug info. The real
problem of course is that reload should never allocate a stack slot
for a simple address calculation that can be rematerialised anywhere
in the function with just one instruction. So after quite a bit of
digging around in reload, I finally figured out that the problem has a
really easy solution. Simply tell reload that those high part address
calculations are constants. Which is true.
That's what the create_TOC_reference change, and the rs6000.md changes
below do. (I also fix large-toc tls patterns.) The rest of the patch
just adjusts for the changed RTL.
Bootstrap and regression tests powerpc64-linux in progress. OK to
apply mainline and 4.6 assuming no regressions?
* config/rs6000/rs6000.c (create_TOC_reference): Wrap high part
of toc-relative address in CONST.
(rs6000_delegitimize_address): Recognize changed address.
(rs6000_legitimize_reload_address): Likewise.
(rs6000_emit_move): Don't force these constants to memory.
* config/rs6000/rs6000.md (tls_gd, tls_gd_high): Wrap high part of
toc-relative address in CONST.
(tls_ld, tls_ld_high, tls_got_dtprel, tls_got_dtprel_high): Likewise.
(tls_got_tprel, tls_got_tprel_high, largetoc_high): Likewise.
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c (revision 175175)
+++ gcc/config/rs6000/rs6000.c (working copy)
@@ -5803,12 +5803,13 @@ rs6000_delegitimize_address (rtx orig_x)
|| TARGET_MINIMAL_TOC
|| TARGET_CMODEL != CMODEL_SMALL))
|| (TARGET_CMODEL != CMODEL_SMALL
- && GET_CODE (XEXP (x, 0)) == PLUS
- && GET_CODE (XEXP (XEXP (x, 0), 0)) == REG
- && REGNO (XEXP (XEXP (x, 0), 0)) == TOC_REGISTER
- && GET_CODE (XEXP (XEXP (x, 0), 1)) == HIGH
+ && GET_CODE (XEXP (x, 0)) == CONST
+ && GET_CODE (XEXP (XEXP (x, 0), 0)) == PLUS
+ && GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 0)) == REG
+ && REGNO (XEXP (XEXP (XEXP (x, 0), 0), 0)) == TOC_REGISTER
+ && GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 1)) == HIGH
&& rtx_equal_p (XEXP (x, 1),
- XEXP (XEXP (XEXP (x, 0), 1), 0)))))
+ XEXP (XEXP (XEXP (XEXP (x, 0), 0), 1), 0)))))
{
y = XVECEXP (y, 0, 0);
if (offset != NULL_RTX)
@@ -6147,11 +6148,12 @@ rs6000_legitimize_reload_address (rtx x,
&& GET_CODE (XEXP (x, 0)) == PLUS
&& GET_CODE (XEXP (XEXP (x, 0), 0)) == REG
&& REGNO (XEXP (XEXP (x, 0), 0)) == TOC_REGISTER
- && GET_CODE (XEXP (XEXP (x, 0), 1)) == HIGH
+ && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST
+ && GET_CODE (XEXP (XEXP (XEXP (x, 0), 1), 0)) == HIGH
&& GET_CODE (XEXP (x, 1)) == CONST
&& GET_CODE (XEXP (XEXP (x, 1), 0)) == UNSPEC
&& XINT (XEXP (XEXP (x, 1), 0), 1) == UNSPEC_TOCREL
- && rtx_equal_p (XEXP (XEXP (XEXP (x, 0), 1), 0), XEXP (x, 1)))
+ && rtx_equal_p (XEXP (XEXP (XEXP (XEXP (x, 0), 1), 0), 0), XEXP (x, 1)))
{
push_reload (XEXP (x, 0), NULL_RTX, &XEXP (x, 0), NULL,
BASE_REG_CLASS, Pmode, VOIDmode, 0, 0,
@@ -7197,6 +7196,11 @@ rs6000_emit_move (rtx dest, rtx source,
}
else if (mode == Pmode
&& CONSTANT_P (operands[1])
+ && GET_CODE (operands[1]) != HIGH
+ && !(TARGET_CMODEL != CMODEL_SMALL
+ && GET_CODE (operands[1]) == CONST
+ && GET_CODE (XEXP (operands[1], 0)) == PLUS
+ && GET_CODE (XEXP (XEXP (operands[1], 0), 1)) == HIGH)
&& ((GET_CODE (operands[1]) != CONST_INT
&& ! easy_fp_constant (operands[1], mode))
|| (GET_CODE (operands[1]) == CONST_INT
@@ -7204,7 +7208,6 @@ rs6000_emit_move (rtx dest, rtx source,
> (TARGET_CMODEL != CMODEL_SMALL ? 3 : 2)))
|| (GET_CODE (operands[0]) == REG
&& FP_REGNO_P (REGNO (operands[0]))))
- && GET_CODE (operands[1]) != HIGH
&& ! legitimate_constant_pool_address_p (operands[1], mode,
false)
&& ! toc_relative_expr_p (operands[1])
@@ -19063,7 +19078,9 @@ create_TOC_reference (rtx symbol, rtx la
tocreg = gen_rtx_REG (Pmode, TOC_REGISTER);
if (TARGET_CMODEL != CMODEL_SMALL)
{
- rtx hi = gen_rtx_PLUS (Pmode, tocreg, gen_rtx_HIGH (Pmode, tocrel));
+ rtx hi = gen_rtx_CONST (Pmode,
+ gen_rtx_PLUS (Pmode, tocreg,
+ gen_rtx_HIGH (Pmode, tocrel)));
if (largetoc_reg != NULL)
{
emit_move_insn (largetoc_reg, hi);
Index: gcc/config/rs6000/rs6000.md
===================================================================
--- gcc/config/rs6000/rs6000.md (revision 175175)
+++ gcc/config/rs6000/rs6000.md (working copy)
@@ -11523,9 +11523,10 @@ (define_insn_and_split "*tls_gd<TLSmode:
"addi %0,%1,%2@got@tlsgd"
"&& TARGET_CMODEL != CMODEL_SMALL"
[(set (match_dup 3)
- (plus:TLSmode (match_dup 1)
- (high:TLSmode
- (unspec:TLSmode [(match_dup 2)] UNSPEC_TLSGD))))
+ (const:TLSmode
+ (plus:TLSmode (match_dup 1)
+ (high:TLSmode
+ (unspec:TLSmode [(match_dup 2)] UNSPEC_TLSGD)))))
(set (match_dup 0)
(lo_sum:TLSmode (match_dup 3)
(unspec:TLSmode [(match_dup 2)] UNSPEC_TLSGD)))]
@@ -11540,10 +11541,11 @@ (define_insn_and_split "*tls_gd<TLSmode:
(define_insn "*tls_gd_high<TLSmode:tls_abi_suffix>"
[(set (match_operand:TLSmode 0 "gpc_reg_operand" "=b")
- (plus:TLSmode (match_operand:TLSmode 1 "gpc_reg_operand" "b")
- (high:TLSmode
- (unspec:TLSmode [(match_operand:TLSmode 2 "rs6000_tls_symbol_ref" "")]
- UNSPEC_TLSGD))))]
+ (const:TLSmode
+ (plus:TLSmode (match_operand:TLSmode 1 "gpc_reg_operand" "b")
+ (high:TLSmode
+ (unspec:TLSmode [(match_operand:TLSmode 2 "rs6000_tls_symbol_ref" "")]
+ UNSPEC_TLSGD)))))]
"HAVE_AS_TLS && TARGET_TLS_MARKERS && TARGET_CMODEL != CMODEL_SMALL"
"addis %0,%1,%2@got@tlsgd@ha"
[(set_attr "length" "4")])
@@ -11658,9 +11660,10 @@ (define_insn_and_split "*tls_ld<TLSmode:
"addi %0,%1,%&@got@tlsld"
"&& TARGET_CMODEL != CMODEL_SMALL"
[(set (match_dup 2)
- (plus:TLSmode (match_dup 1)
- (high:TLSmode
- (unspec:TLSmode [(const_int 0)] UNSPEC_TLSLD))))
+ (const:TLSmode
+ (plus:TLSmode (match_dup 1)
+ (high:TLSmode
+ (unspec:TLSmode [(const_int 0)] UNSPEC_TLSLD)))))
(set (match_dup 0)
(lo_sum:TLSmode (match_dup 2)
(unspec:TLSmode [(const_int 0)] UNSPEC_TLSLD)))]
@@ -11675,9 +11678,10 @@ (define_insn_and_split "*tls_ld<TLSmode:
(define_insn "*tls_ld_high<TLSmode:tls_abi_suffix>"
[(set (match_operand:TLSmode 0 "gpc_reg_operand" "=b")
- (plus:TLSmode (match_operand:TLSmode 1 "gpc_reg_operand" "b")
- (high:TLSmode
- (unspec:TLSmode [(const_int 0)] UNSPEC_TLSLD))))]
+ (const:TLSmode
+ (plus:TLSmode (match_operand:TLSmode 1 "gpc_reg_operand" "b")
+ (high:TLSmode
+ (unspec:TLSmode [(const_int 0)] UNSPEC_TLSLD)))))]
"HAVE_AS_TLS && TARGET_TLS_MARKERS && TARGET_CMODEL != CMODEL_SMALL"
"addis %0,%1,%&@got@tlsld@ha"
[(set_attr "length" "4")])
@@ -11753,9 +11757,10 @@ (define_insn_and_split "tls_got_dtprel_<
"l<TLSmode:tls_insn_suffix> %0,%2@got@dtprel(%1)"
"&& TARGET_CMODEL != CMODEL_SMALL"
[(set (match_dup 3)
- (plus:TLSmode (match_dup 1)
- (high:TLSmode
- (unspec:TLSmode [(match_dup 2)] UNSPEC_TLSGOTDTPREL))))
+ (const:TLSmode
+ (plus:TLSmode (match_dup 1)
+ (high:TLSmode
+ (unspec:TLSmode [(match_dup 2)] UNSPEC_TLSGOTDTPREL)))))
(set (match_dup 0)
(lo_sum:TLSmode (match_dup 3)
(unspec:TLSmode [(match_dup 2)] UNSPEC_TLSGOTDTPREL)))]
@@ -11770,10 +11775,11 @@ (define_insn_and_split "tls_got_dtprel_<
(define_insn "*tls_got_dtprel_high<TLSmode:tls_abi_suffix>"
[(set (match_operand:TLSmode 0 "gpc_reg_operand" "=b")
- (plus:TLSmode (match_operand:TLSmode 1 "gpc_reg_operand" "b")
- (high:TLSmode
- (unspec:TLSmode [(match_operand:TLSmode 2 "rs6000_tls_symbol_ref" "")]
- UNSPEC_TLSGOTDTPREL))))]
+ (const:TLSmode
+ (plus:TLSmode (match_operand:TLSmode 1 "gpc_reg_operand" "b")
+ (high:TLSmode
+ (unspec:TLSmode [(match_operand:TLSmode 2 "rs6000_tls_symbol_ref" "")]
+ UNSPEC_TLSGOTDTPREL)))))]
"HAVE_AS_TLS && TARGET_CMODEL != CMODEL_SMALL"
"addis %0,%1,%2@got@dtprel@ha"
[(set_attr "length" "4")])
@@ -11823,9 +11829,10 @@ (define_insn_and_split "tls_got_tprel_<T
"l<TLSmode:tls_insn_suffix> %0,%2@got@tprel(%1)"
"&& TARGET_CMODEL != CMODEL_SMALL"
[(set (match_dup 3)
- (plus:TLSmode (match_dup 1)
- (high:TLSmode
- (unspec:TLSmode [(match_dup 2)] UNSPEC_TLSGOTTPREL))))
+ (const:TLSmode
+ (plus:TLSmode (match_dup 1)
+ (high:TLSmode
+ (unspec:TLSmode [(match_dup 2)] UNSPEC_TLSGOTTPREL)))))
(set (match_dup 0)
(lo_sum:TLSmode (match_dup 3)
(unspec:TLSmode [(match_dup 2)] UNSPEC_TLSGOTTPREL)))]
@@ -11840,10 +11847,11 @@ (define_insn_and_split "tls_got_tprel_<T
(define_insn "*tls_got_tprel_high<TLSmode:tls_abi_suffix>"
[(set (match_operand:TLSmode 0 "gpc_reg_operand" "=b")
- (plus:TLSmode (match_operand:TLSmode 1 "gpc_reg_operand" "b")
- (high:TLSmode
- (unspec:TLSmode [(match_operand:TLSmode 2 "rs6000_tls_symbol_ref" "")]
- UNSPEC_TLSGOTTPREL))))]
+ (const:TLSmode
+ (plus:TLSmode (match_operand:TLSmode 1 "gpc_reg_operand" "b")
+ (high:TLSmode
+ (unspec:TLSmode [(match_operand:TLSmode 2 "rs6000_tls_symbol_ref" "")]
+ UNSPEC_TLSGOTTPREL)))))]
"HAVE_AS_TLS && TARGET_CMODEL != CMODEL_SMALL"
"addis %0,%1,%2@got@tprel@ha"
[(set_attr "length" "4")])
@@ -12157,8 +12165,9 @@ (define_insn "elf_low"
;; Largetoc support
(define_insn "largetoc_high"
[(set (match_operand:DI 0 "gpc_reg_operand" "=b")
- (plus:DI (match_operand:DI 1 "gpc_reg_operand" "b")
- (high:DI (match_operand:DI 2 "" ""))))]
+ (const:DI
+ (plus:DI (match_operand:DI 1 "gpc_reg_operand" "b")
+ (high:DI (match_operand:DI 2 "" "")))))]
"TARGET_ELF && TARGET_CMODEL != CMODEL_SMALL"
"{cau|addis} %0,%1,%2@ha")
--
Alan Modra
Australia Development Lab, IBM
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