From: Bernd Schmidt Date: Mon, 12 Dec 2016 13:01:28 +0000 (+0000) Subject: backport: re PR tree-optimization/77309 (wrong code at -Os and above on x86_64-linux... X-Git-Tag: releases/gcc-5.5.0~650 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e361da2c6fd293b43a44e66f4283fac7c6d0c5ff;p=thirdparty%2Fgcc.git backport: re PR tree-optimization/77309 (wrong code at -Os and above on x86_64-linux-gnu (in the 64-bit mode)) Backport from mainline 2016-11-07 Bernd Schmidt PR rtl-optimization/77309 * combine.c (make_compound_operation): Allow EQ for IN_CODE, and don't assume an equality comparison for plain COMPARE. (simplify_comparison): Pass a more accurate code to make_compound_operation. PR rtl-optimization/77309 * gcc.dg/torture/pr77309.c: New test. From-SVN: r243550 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f47615b4225c..a6b3df545cde 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,14 @@ +2016-12-12 Bernd Schmidt + + Backport from mainline + 2016-11-07 Bernd Schmidt + + PR rtl-optimization/77309 + * combine.c (make_compound_operation): Allow EQ for IN_CODE, and + don't assume an equality comparison for plain COMPARE. + (simplify_comparison): Pass a more accurate code to + make_compound_operation. + 2016-12-07 Segher Boessenkool Backport from mainline diff --git a/gcc/combine.c b/gcc/combine.c index fb3215370deb..a6c134458582 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -7726,10 +7726,12 @@ extract_left_shift (rtx x, int count) We try, as much as possible, to re-use rtl expressions to save memory. - IN_CODE says what kind of expression we are processing. Normally, it is - SET. In a memory address (inside a MEM, PLUS or minus, the latter two - being kludges), it is MEM. When processing the arguments of a comparison - or a COMPARE against zero, it is COMPARE. */ + IN_CODE says what kind of expression we are processing. Normally, + it is SET. In a memory address (inside a MEM, PLUS or minus, the + latter two being kludges), it is MEM. When processing the + arguments of a comparison or a COMPARE against zero, it is COMPARE, + or EQ if more + precisely it is an equality comparison against + zero.. */ rtx make_compound_operation (rtx x, enum rtx_code in_code) @@ -7743,11 +7745,17 @@ make_compound_operation (rtx x, enum rtx_code in_code) rtx new_rtx = 0; rtx tem; const char *fmt; + bool equality_comparison = false; /* Select the code to be used in recursive calls. Once we are inside an address, we stay there. If we have a comparison, set to COMPARE, but once inside, go back to our default of SET. */ + if (in_code == EQ) + { + equality_comparison = true; + in_code = COMPARE; + } next_code = (code == MEM ? MEM : ((code == PLUS || code == MINUS) && SCALAR_INT_MODE_P (mode)) ? MEM @@ -7935,11 +7943,12 @@ make_compound_operation (rtx x, enum rtx_code in_code) /* If we are in a comparison and this is an AND with a power of two, convert this into the appropriate bit extract. */ else if (in_code == COMPARE - && (i = exact_log2 (UINTVAL (XEXP (x, 1)))) >= 0) + && (i = exact_log2 (UINTVAL (XEXP (x, 1)))) >= 0 + && (equality_comparison || i < GET_MODE_PRECISION (mode) - 1)) new_rtx = make_extraction (mode, - make_compound_operation (XEXP (x, 0), - next_code), - i, NULL_RTX, 1, 1, 0, 1); + make_compound_operation (XEXP (x, 0), + next_code), + i, NULL_RTX, 1, 1, 0, 1); break; @@ -12253,7 +12262,11 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1) We can never remove a SUBREG for a non-equality comparison because the sign bit is in a different place in the underlying object. */ - op0 = make_compound_operation (op0, op1 == const0_rtx ? COMPARE : SET); + rtx_code op0_mco_code = SET; + if (op1 == const0_rtx) + op0_mco_code = code == NE || code == EQ ? EQ : COMPARE; + + op0 = make_compound_operation (op0, op0_mco_code); op1 = make_compound_operation (op1, SET); if (GET_CODE (op0) == SUBREG && subreg_lowpart_p (op0) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index c560323c275f..f09906befb99 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,11 @@ +2016-12-12 Bernd Schmidt + + Backport from mainline + 2016-11-07 Bernd Schmidt + + PR rtl-optimization/77309 + * gcc.dg/torture/pr77309.c: New test. + 2016-12-08 Nathan Sidwell PR c++/78551 diff --git a/gcc/testsuite/gcc.dg/torture/pr77309.c b/gcc/testsuite/gcc.dg/torture/pr77309.c new file mode 100644 index 000000000000..5bdbc0a0b83a --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr77309.c @@ -0,0 +1,14 @@ +/* { dg-do run } */ + +int a, b; + +int main () +{ + long c = 1 % (2 ^ b); + c = -c & ~(~(b ^ ~b) || a); + + if (c >= 0) + __builtin_abort (); + + return 0; +}