| Message ID | 5614556E.5020908@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Wed, Oct 7, 2015 at 1:12 AM, kugan <kugan.vivekanandarajah@linaro.org> wrote: > > Hi Richard, > > Thanks for the review. > > On 15/09/15 23:08, Richard Biener wrote: >> >> On Mon, Sep 7, 2015 at 4:58 AM, Kugan <kugan.vivekanandarajah@linaro.org> >> wrote: >>> >>> This patch tree-vrp handling and optimization for ZEXT_EXPR. >> >> >> + else if (code == SEXT_EXPR) >> + { >> + gcc_assert (range_int_cst_p (&vr1)); >> + unsigned int prec = tree_to_uhwi (vr1.min); >> + type = vr0.type; >> + wide_int tmin, tmax; >> + wide_int type_min, type_max; >> + wide_int may_be_nonzero, must_be_nonzero; >> + >> + gcc_assert (!TYPE_UNSIGNED (expr_type)); >> >> hmm, I don't think we should restrict SEXT_EXPR this way. SEXT_EXPR >> should operate on both signed and unsigned types and the result type >> should be the same as the type of operand 0. >> >> + type_min = wi::shwi (1 << (prec - 1), >> + TYPE_PRECISION (TREE_TYPE (vr0.min))); >> + type_max = wi::shwi (((1 << (prec - 1)) - 1), >> + TYPE_PRECISION (TREE_TYPE (vr0.max))); >> >> there is wi::min_value and max_value for this. > > > As of now, SEXT_EXPR in gimple is of the form: x = y sext 8 and types of all > the operand and results are of the wider type. Therefore we cant use the > wi::min_value. Or do you want to convert this precision (in this case 8) to > a type and use wi::min_value? I don't understand - wi::min/max_value get a precision and sign, not a type. your 1 << (prec - 1) is even wrong for prec > 32 (it's an integer type expression). Thus type_min = wi::min_value (prec, SIGNED); type_max = wi::max_value (prec, SIGNED); ? > Please find the patch that addresses the other comments. I'll have a look later. > Thanks, > Kugan > > >> >> + HOST_WIDE_INT int_may_be_nonzero = may_be_nonzero.to_uhwi (); >> + HOST_WIDE_INT int_must_be_nonzero = must_be_nonzero.to_uhwi (); >> >> this doesn't need to fit a HOST_WIDE_INT, please use wi::bit_and (can't >> find a test_bit with a quick search). >> >> + tmin = wi::sext (tmin, prec - 1); >> + tmax = wi::sext (tmax, prec - 1); >> + min = wide_int_to_tree (expr_type, tmin); >> + max = wide_int_to_tree (expr_type, tmax); >> >> not sure why you need the extra sign-extensions here. >> >> + case SEXT_EXPR: >> + { >> + gcc_assert (is_gimple_min_invariant (op1)); >> + unsigned int prec = tree_to_uhwi (op1); >> >> no need to assert, tree_to_uhwi will do that for you. >> >> + HOST_WIDE_INT may_be_nonzero = may_be_nonzero0.to_uhwi (); >> + HOST_WIDE_INT must_be_nonzero = must_be_nonzero0.to_uhwi (); >> >> likewise with HOST_WIDE__INT issue. >> >> Otherwise looks ok to me. Btw, this and adding of SEXT_EXPR could be >> accompanied with a match.pd pattern detecting sign-extension patterns, >> that would give some extra test coverage. >> >> Thanks, >> Richard. >> >>> >>> >>> gcc/ChangeLog: >>> >>> 2015-09-07 Kugan Vivekanandarajah <kuganv@linaro.org> >>> >>> * tree-vrp.c (extract_range_from_binary_expr_1): Handle >>> SEXT_EXPR. >>> (simplify_bit_ops_using_ranges): Likewise. >>> (simplify_stmt_using_ranges): Likewise.
From 75fb9b8bcacd36a1409bf94c38048de83a5eab62 Mon Sep 17 00:00:00 2001 From: Kugan Vivekanandarajah <kugan.vivekanandarajah@linaro.org> Date: Mon, 17 Aug 2015 13:45:52 +1000 Subject: [PATCH 3/7] Optimize ZEXT_EXPR with tree-vrp --- gcc/tree-vrp.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index 2cd71a2..9c7d8d8 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -2317,6 +2317,7 @@ extract_range_from_binary_expr_1 (value_range_t *vr, && code != LSHIFT_EXPR && code != MIN_EXPR && code != MAX_EXPR + && code != SEXT_EXPR && code != BIT_AND_EXPR && code != BIT_IOR_EXPR && code != BIT_XOR_EXPR) @@ -2877,6 +2878,53 @@ extract_range_from_binary_expr_1 (value_range_t *vr, extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1); return; } + else if (code == SEXT_EXPR) + { + gcc_assert (range_int_cst_p (&vr1)); + unsigned int prec = tree_to_uhwi (vr1.min); + type = vr0.type; + wide_int tmin, tmax; + wide_int sign_bit; + wide_int type_min, type_max; + wide_int may_be_nonzero, must_be_nonzero; + + type_min = wi::shwi (1 << (prec - 1), + TYPE_PRECISION (TREE_TYPE (vr0.min))); + type_max = wi::shwi (((1 << (prec - 1)) - 1), + TYPE_PRECISION (TREE_TYPE (vr0.max))); + sign_bit = wi::shwi (1 << (prec - 1), + TYPE_PRECISION (TREE_TYPE (vr0.min))); + if (zero_nonzero_bits_from_vr (expr_type, &vr0, + &may_be_nonzero, + &must_be_nonzero)) + { + if (wi::bit_and (must_be_nonzero, sign_bit) == sign_bit) + { + /* If to-be-extended sign bit is one. */ + tmin = type_min; + tmax = may_be_nonzero; + } + else if (wi::bit_and (may_be_nonzero, sign_bit) + != sign_bit) + { + /* If to-be-extended sign bit is zero. */ + tmin = must_be_nonzero; + tmax = may_be_nonzero; + } + else + { + tmin = type_min; + tmax = type_max; + } + } + else + { + tmin = type_min; + tmax = type_max; + } + min = wide_int_to_tree (expr_type, tmin); + max = wide_int_to_tree (expr_type, tmax); + } else if (code == RSHIFT_EXPR || code == LSHIFT_EXPR) { @@ -9244,6 +9292,30 @@ simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) break; } break; + case SEXT_EXPR: + { + gcc_assert (is_gimple_min_invariant (op1)); + unsigned int prec = tree_to_uhwi (op1); + wide_int mask, sign_bit; + mask = wi::shwi (((1 << (prec - 1)) - 1), + TYPE_PRECISION (TREE_TYPE (vr0.max))); + mask = wi::bit_not (mask); + sign_bit = wi::shwi (1 << (prec - 1), + TYPE_PRECISION (TREE_TYPE (vr0.min))); + if (wi::bit_and (must_be_nonzero0, sign_bit) == sign_bit) + { + /* If to-be-extended sign bit is one. */ + if (wi::bit_and (must_be_nonzero0, mask) == mask) + op = op0; + } + else if (wi::bit_and (may_be_nonzero0, sign_bit) != sign_bit) + { + /* If to-be-extended sign bit is zero. */ + if (wi::bit_and (may_be_nonzero0, mask) == 0) + op = op0; + } + } + break; default: gcc_unreachable (); } @@ -9946,6 +10018,7 @@ simplify_stmt_using_ranges (gimple_stmt_iterator *gsi) case BIT_AND_EXPR: case BIT_IOR_EXPR: + case SEXT_EXPR: /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR if all the bits being cleared are already cleared or all the bits being set are already set. */ -- 1.9.1