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[58.6.183.210]) by mx.google.com with ESMTPSA id tf10sm9138115pbc.70.2014.07.13.19.57.59 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sun, 13 Jul 2014 19:58:01 -0700 (PDT) Message-ID: <53C34734.2080103@linaro.org> Date: Mon, 14 Jul 2014 12:57:56 +1000 From: Kugan User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Richard Biener CC: Jakub Jelinek , "gcc-patches@gcc.gnu.org" Subject: Re: [PATCH 2/2] Enable elimination of zext/sext References: <53A9658F.2070304@linaro.org> <53A966BF.30806@linaro.org> <20140624122101.GX31640@tucnak.redhat.com> <53AA8501.809@linaro.org> <20140625083618.GZ31640@tucnak.redhat.com> <53BA4458.30804@linaro.org> <53BFD000.1030909@linaro.org> In-Reply-To: X-IsSubscribed: yes On 11/07/14 22:47, Richard Biener wrote: > On Fri, Jul 11, 2014 at 1:52 PM, Kugan > wrote: >> Thanks foe the review and suggestions. >> >> On 10/07/14 22:15, Richard Biener wrote: >>> On Mon, Jul 7, 2014 at 8:55 AM, Kugan wrote: >> >> [...] >> >>>> >>>> For -fwrapv, it is due to how PROMOTE_MODE is defined in arm back-end. >>>> In the test-case, a function (which has signed char return type) returns >>>> -1 in one of the paths. ARM PROMOTE_MODE changes that to 255 and relies >>>> on zero/sign extension generated by RTL again for the correct value. I >>>> saw some other targets also defining similar think. I am therefore >>>> skipping removing zero/sign extension if the ssa variable can be set to >>>> negative integer constants. >>> >>> Hm? I think you should rather check that you are removing a >>> sign-/zero-extension - PROMOTE_MODE tells you if it will sign- or >>> zero-extend. Definitely >>> >>> + /* In some architectures, negative integer constants are truncated and >>> + sign changed with target defined PROMOTE_MODE macro. This will impact >>> + the value range seen here and produce wrong code if zero/sign extensions >>> + are eliminated. Therefore, return false if this SSA can have negative >>> + integers. */ >>> + if (is_gimple_assign (stmt) >>> + && (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_unary)) >>> + { >>> + tree rhs1 = gimple_assign_rhs1 (stmt); >>> + if (TREE_CODE (rhs1) == INTEGER_CST >>> + && !TYPE_UNSIGNED (TREE_TYPE (ssa)) >>> + && tree_int_cst_compare (rhs1, integer_zero_node) == -1) >>> + return false; >>> >>> looks completely bogus ... (an unary op with a constant operand?) >>> instead you want to do sth like >> >> I see that unary op with a constant operand is not possible in gimple. >> What I wanted to check here is any sort of constant loads; but seems >> that will not happen in gimple. Is PHI statements the only possible >> statements where we will end up with such constants. > > No, in theory you can have > > ssa_1 = -1; > > but that's not unary but a GIMPLE_SINGLE_RHS and thus > gimple_assign_rhs_code (stmt) == INTEGER_CST. > >>> mode = TYPE_MODE (TREE_TYPE (ssa)); >>> rhs_uns = TYPE_UNSIGNED (TREE_TYPE (ssa)); >>> PROMOTE_MODE (mode, rhs_uns, TREE_TYPE (ssa)); >>> >>> instead of initializing rhs_uns from ssas type. That is, if >>> PROMOTE_MODE tells you to promote _not_ according to ssas sign then >>> honor that. >> >> This is triggered in pr43017.c in function foo for arm-none-linux-gnueabi. >> >> where, the gimple statement that cause this looks like: >> ..... >> # _3 = PHI <_17(7), -1(2)> >> bb43: >> return _3; >> >> ARM PROMOTE_MODE changes the sign for integer constants only and hence >> looking at the variable with PROMOTE_MODE is not changing the sign in >> this case. >> >> #define PROMOTE_MODE(MODE, UNSIGNEDP, TYPE) \ >> if (GET_MODE_CLASS (MODE) == MODE_INT \ >> && GET_MODE_SIZE (MODE) < 4) \ >> { \ >> if (MODE == QImode) \ >> UNSIGNEDP = 1; \ >> else if (MODE == HImode) \ >> UNSIGNEDP = 1; \ >> (MODE) = SImode; \ >> } > > Where does it only apply for "constants"? It applies to all QImode and > HImode entities. oops, sorry. I don’t know what I was thinking or looking at when I wrote that :( It indeed fixes my problems. Thanks for that. Here is the modified patch. Bootstrapped and regression tested for 86_64-unknown-linux-gnu and arm-none-linux-gnueabi with no new regressions. Is this OK? Thanks, Kugan gcc/ 2014-07-14 Kugan Vivekanandarajah * calls.c (precompute_arguments): Check is_promoted_for_type and set the promoted mode. (is_promoted_for_type): New function. (expand_expr_real_1): Check is_promoted_for_type and set the promoted mode. * expr.h (is_promoted_for_type): New function definition. * cfgexpand.c (expand_gimple_stmt_1): Call emit_move_insn if SUBREG is promoted with SRP_SIGNED_AND_UNSIGNED. gcc/testsuite 2014-07-14 Kugan Vivekanandarajah * gcc.dg/zero_sign_ext_test.c: New test. diff --git a/gcc/calls.c b/gcc/calls.c index a3e6faa..eac512f 100644 --- a/gcc/calls.c +++ b/gcc/calls.c @@ -1484,7 +1484,10 @@ precompute_arguments (int num_actuals, struct arg_data *args) args[i].initial_value = gen_lowpart_SUBREG (mode, args[i].value); SUBREG_PROMOTED_VAR_P (args[i].initial_value) = 1; - SUBREG_PROMOTED_SET (args[i].initial_value, args[i].unsignedp); + if (is_promoted_for_type (args[i].tree_value, mode, !args[i].unsignedp)) + SUBREG_PROMOTED_SET (args[i].initial_value, SRP_SIGNED_AND_UNSIGNED); + else + SUBREG_PROMOTED_SET (args[i].initial_value, args[i].unsignedp); } } } diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c index f98c322..b14626c 100644 --- a/gcc/cfgexpand.c +++ b/gcc/cfgexpand.c @@ -3309,7 +3309,13 @@ expand_gimple_stmt_1 (gimple stmt) GET_MODE (target), temp, unsignedp); } - convert_move (SUBREG_REG (target), temp, unsignedp); + if ((SUBREG_PROMOTED_GET (target) == SRP_SIGNED_AND_UNSIGNED) + && (GET_CODE (temp) == SUBREG) + && (GET_MODE (target) == GET_MODE (temp)) + && (GET_MODE (SUBREG_REG (target)) == GET_MODE (SUBREG_REG (temp)))) + emit_move_insn (SUBREG_REG (target), SUBREG_REG (temp)); + else + convert_move (SUBREG_REG (target), temp, unsignedp); } else if (nontemporal && emit_storent_insn (target, temp)) ; diff --git a/gcc/expr.c b/gcc/expr.c index 7356e76..d25f506 100644 --- a/gcc/expr.c +++ b/gcc/expr.c @@ -68,6 +68,7 @@ along with GCC; see the file COPYING3. If not see #include "tree-ssa-address.h" #include "cfgexpand.h" #include "builtins.h" +#include "tree-ssa.h" #ifndef STACK_PUSH_CODE #ifdef STACK_GROWS_DOWNWARD @@ -9224,6 +9225,65 @@ expand_expr_real_2 (sepops ops, rtx target, enum machine_mode tmode, } #undef REDUCE_BIT_FIELD +/* Return TRUE if value in SSA is already zero/sign extended for lhs type + (type here is the combination of LHS_MODE and LHS_UNS) using value range + information stored. Return FALSE otherwise. */ +bool +is_promoted_for_type (tree ssa, enum machine_mode lhs_mode, bool lhs_uns) +{ + wide_int type_min, type_max; + wide_int min, max, limit; + unsigned int prec; + tree lhs_type; + bool rhs_uns; + enum machine_mode mode; + + if (ssa == NULL_TREE + || TREE_CODE (ssa) != SSA_NAME + || !INTEGRAL_TYPE_P (TREE_TYPE (ssa))) + return false; + + /* Return FALSE if value_range is not recorded for SSA. */ + if (get_range_info (ssa, &min, &max) != VR_RANGE) + return false; + + /* In some architectures, modes are promoted and sign changed with + target defined PROMOTE_MODE macro. If PROMOTE_MODE tells you to + promote _not_ according to ssa's sign then honour that. */ + mode = TYPE_MODE (TREE_TYPE (ssa)); + rhs_uns = TYPE_UNSIGNED (TREE_TYPE (ssa)); + PROMOTE_MODE (mode, rhs_uns, TREE_TYPE (ssa)); + + lhs_type = lang_hooks.types.type_for_mode (lhs_mode, lhs_uns); + prec = min.get_precision (); + + /* Signed maximum value. */ + limit = wide_int::from (TYPE_MAX_VALUE (TREE_TYPE (ssa)), prec, SIGNED); + + /* Signedness of LHS and RHS differs but values in range. */ + if ((rhs_uns != lhs_uns) + && ((!lhs_uns && !wi::neg_p (min, TYPE_SIGN (lhs_type))) + || (lhs_uns && (wi::cmp (max, limit, TYPE_SIGN (TREE_TYPE (ssa))) == -1)))) + lhs_uns = !lhs_uns; + + /* Signedness of LHS and RHS should match. */ + if (rhs_uns != lhs_uns) + return false; + + type_min = wide_int::from (TYPE_MIN_VALUE (lhs_type), prec, + TYPE_SIGN (TREE_TYPE (ssa))); + type_max = wide_int::from (TYPE_MAX_VALUE (lhs_type), prec, + TYPE_SIGN (TREE_TYPE (ssa))); + + /* Check if values lies in-between the type range. */ + if ((wi::neg_p (max, TYPE_SIGN (TREE_TYPE (ssa))) + || (wi::cmp (max, type_max, TYPE_SIGN (TREE_TYPE (ssa))) != 1)) + && (!wi::neg_p (min, TYPE_SIGN (TREE_TYPE (ssa))) + || (wi::cmp (type_min, min, TYPE_SIGN (TREE_TYPE (ssa))) != 1))) + return true; + + return false; +} /* Return TRUE if expression STMT is suitable for replacement. Never consider memory loads as replaceable, because those don't ever lead @@ -9527,7 +9587,10 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode, temp = gen_lowpart_SUBREG (mode, decl_rtl); SUBREG_PROMOTED_VAR_P (temp) = 1; - SUBREG_PROMOTED_SET (temp, unsignedp); + if (is_promoted_for_type (ssa_name, mode, !unsignedp)) + SUBREG_PROMOTED_SET (temp, SRP_SIGNED_AND_UNSIGNED); + else + SUBREG_PROMOTED_SET (temp, unsignedp); return temp; } diff --git a/gcc/expr.h b/gcc/expr.h index 6a1d3ab..e99d000 100644 --- a/gcc/expr.h +++ b/gcc/expr.h @@ -440,6 +440,7 @@ extern rtx expand_expr_real_1 (tree, rtx, enum machine_mode, enum expand_modifier, rtx *, bool); extern rtx expand_expr_real_2 (sepops, rtx, enum machine_mode, enum expand_modifier); +extern bool is_promoted_for_type (tree, enum machine_mode, bool); /* Generate code for computing expression EXP. An rtx for the computed value is returned. The value is never null. diff --git a/gcc/testsuite/gcc.dg/zero_sign_ext_test.c b/gcc/testsuite/gcc.dg/zero_sign_ext_test.c index e69de29..6a52678 100644 --- a/gcc/testsuite/gcc.dg/zero_sign_ext_test.c +++ b/gcc/testsuite/gcc.dg/zero_sign_ext_test.c @@ -0,0 +1,136 @@ +extern void abort (void); + +/* { dg-options "-O2" } */ +/* { dg-do run } */ + +#define TYPE_MAX(type, sign) \ + ((!sign) ? ((1 << (sizeof (type) * 8 - 1)) - 1) : \ + ((1 << (sizeof (type) * 8)) - 1)) +#define TYPE_MIN(type, sign) \ + ((!sign) ? -(1 << (sizeof (type) * 8 - 1)) : 0) + +#define TEST_FN(NAME, ARG_TYPE, RET_TYPE, CAST_TYPE, VAL, VR_MIN, VR_MAX)\ + __attribute__((noinline, noclone)) RET_TYPE \ + NAME (ARG_TYPE arg){ \ + RET_TYPE ret = VAL; \ + if (arg + 1 < VR_MIN || arg + 1 > VR_MAX) return ret; \ + /* Value Range of arg at this point will be [VR_min, VR_max]. */\ + arg = arg + VAL; \ + ret = (CAST_TYPE)arg; \ + return arg; \ + } + +/* Signed to signed conversion with value in-range. */ +TEST_FN (foo1, short, short, char, 1, TYPE_MIN (char, 0), TYPE_MAX (char, 0)); +TEST_FN (foo2, short, short, char, 1, TYPE_MIN (char, 0) + 1,\ + TYPE_MAX (char, 0) - 1); + +/* Signed to signed conversion with value not in-range. */ +TEST_FN (foo3, short, short, char, -1, TYPE_MIN (short, 0) + 1, 100); +TEST_FN (foo4, short, short, char, 1, 12, TYPE_MAX (short, 0) + 1); + +/* Unsigned to unsigned conversion with value in-range. */ +TEST_FN (foo5, unsigned short, unsigned short, unsigned char, 1,\ + TYPE_MIN (char, 1) + 1, TYPE_MAX (char, 1) - 1); +TEST_FN (foo6, unsigned short, unsigned short, unsigned char, 1,\ + TYPE_MIN (char, 1), TYPE_MAX (char, 1)); + +/* Unsigned to unsigned conversion with value not in-range. */ +TEST_FN (foo7, unsigned short, unsigned short, unsigned char, 1,\ + TYPE_MIN (short, 1) + 1, TYPE_MAX (short, 1) - 1); +TEST_FN (foo8, unsigned short, unsigned short, unsigned char, 1,\ + TYPE_MIN (short, 1), TYPE_MAX (short, 1)); + +/* Signed to unsigned conversion with value range positive. */ +TEST_FN (foo9, short, short, unsigned char, -1, 1,\ + TYPE_MAX (char, 1) - 1); +TEST_FN (foo10, short, short, unsigned char, 1, 0,\ + TYPE_MAX (char, 1)); + +/* Signed to unsigned conversion with value range negative. */ +TEST_FN (foo11, short, short, unsigned char, 1,\ + TYPE_MIN (char, 0) + 1, TYPE_MAX (char, 0) - 1); +TEST_FN (foo12, short, short, unsigned char, 1,\ + TYPE_MIN (char, 0), TYPE_MAX (char, 0)); + +/* Unsigned to Signed conversion with value range in signed equiv range. */ +TEST_FN (foo13, unsigned short, unsigned short, char, 1,\ + TYPE_MIN (char, 1) + 1, TYPE_MAX (char, 0) - 1); +TEST_FN (foo14, unsigned short, unsigned short, char, 1,\ + TYPE_MIN (char, 1), TYPE_MAX (char, 0)); + +/* Unsigned to Signed conversion with value range not-in signed range. */ +TEST_FN (foo15, unsigned short, unsigned short, char, 1,\ + TYPE_MIN (char, 1) + 1, TYPE_MAX (char, 1) - 1); +TEST_FN (foo16, unsigned short, unsigned short, char, 1,\ + TYPE_MIN (char, 1), TYPE_MAX (char, 1)); + +int main () +{ + /* Signed to signed conversion with value in-range. */ + /* arg + 1. */ + if (foo1 (-32) != -31) + abort (); + /* arg + 1. */ + if (foo2 (32) != 33) + abort (); + + /* Signed to signed conversion with value not in-range. */ + /* arg - 1. */ + if (foo3 (-512) != -513) + abort (); + /* arg + 1. */ + if (foo4 (512) != 513) + abort (); + + /* Unsigned to unsigned conversion with value in-range. */ + /* arg + 1. */ + if (foo5 (64) != 65) + abort (); + /* arg + 1. */ + if (foo6 (64) != 65) + abort (); + + /* Unsigned to unsigned conversion with value not in-range. */ + /* arg + 1. */ + if (foo7 (512) != 513) + abort (); + /* arg + 1. */ + if (foo8 (512) != 513) + abort (); + + /* Signed to unsigned conversion with value range positive. */ + /* arg - 1. */ + if (foo9 (2) != 1) + abort (); + /* arg + 1. */ + if (foo10 (2) != 3) + abort (); + + /* Signed to unsigned conversion with value range negative. */ + /* arg + 1. */ + if (foo11 (-125) != -124) + abort (); + /* arg + 1. */ + if (foo12 (-125) != -124) + abort (); + + /* Unsigned to Signed conversion with value range in signed equiv range. */ + /* arg + 1. */ + if (foo13 (125) != 126) + abort (); + /* arg + 1. */ + if (foo14 (125) != 126) + abort (); + + /* Unsigned to Signed conversion with value range not-in signed range. */ + /* arg + 1. */ + if (foo15 (250) != 251) + abort (); + /* arg + 1. */ + if (foo16 (250) != 251) + abort (); + + return 0; +} +