From d480e6a572799f809744075cdf447f959753b173 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Mon, 21 Oct 2013 11:34:04 +0000 Subject: [PATCH] re PR middle-end/58742 (pointer arithmetic simplification) 2013-10-21 Richard Biener PR middle-end/58742 * fold-const.c (fold_binary_loc): Fold ((T) (X /[ex] C)) * C to (T) X for sign-changing conversions (or no conversion). * c-c++-common/fold-divmul-1.c: New testcase. From-SVN: r203890 --- gcc/ChangeLog | 6 ++++++ gcc/fold-const.c | 7 +++++++ gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/c-c++-common/fold-divmul-1.c | 11 +++++++++++ 4 files changed, 29 insertions(+) create mode 100644 gcc/testsuite/c-c++-common/fold-divmul-1.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index bbcc371ae71..99b921abfbd 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2013-10-21 Richard Biener + + PR middle-end/58742 + * fold-const.c (fold_binary_loc): Fold ((T) (X /[ex] C)) * C + to (T) X for sign-changing conversions (or no conversion). + 2013-10-20 Uros Bizjak * config/i386/i386.md (kxnor): Add FLAGS_REG clobber. diff --git a/gcc/fold-const.c b/gcc/fold-const.c index c4c09b65eb1..2a184109ea1 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -11002,6 +11002,13 @@ fold_binary_loc (location_t loc, fold_build2_loc (loc, MULT_EXPR, type, build_int_cst (type, 2) , arg1)); + /* ((T) (X /[ex] C)) * C cancels out if the conversion is + sign-changing only. */ + if (TREE_CODE (arg1) == INTEGER_CST + && TREE_CODE (arg0) == EXACT_DIV_EXPR + && operand_equal_p (arg1, TREE_OPERAND (arg0, 1), 0)) + return fold_convert_loc (loc, type, TREE_OPERAND (arg0, 0)); + strict_overflow_p = false; if (TREE_CODE (arg1) == INTEGER_CST && 0 != (tem = extract_muldiv (op0, arg1, code, NULL_TREE, diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 7acbd3b9b9e..6add22c389e 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2013-10-21 Richard Biener + + PR middle-end/58742 + * c-c++-common/fold-divmul-1.c: New testcase. + 2013-10-21 Michael Zolotukhin * gcc.target/i386/memset-vector_loop-1.c: New test. diff --git a/gcc/testsuite/c-c++-common/fold-divmul-1.c b/gcc/testsuite/c-c++-common/fold-divmul-1.c new file mode 100644 index 00000000000..5c867923d2e --- /dev/null +++ b/gcc/testsuite/c-c++-common/fold-divmul-1.c @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-options "-fdump-tree-original" } */ + +int * +fx (int *b, int *e) +{ + return b + (e - b); +} + +/* { dg-final { scan-tree-dump-not "/\\\[ex\\\]" "original" } } */ +/* { dg-final { cleanup-tree-dump "original" } } */ -- 2.30.2