From 85eaf6c6a3678d7eb19552a8a6f58018e6892115 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Thu, 8 Nov 2018 08:03:12 +0000 Subject: re PR target/87913 (max(n, 1) code generation) 2018-11-08 Richard Biener PR tree-optimization/87913 * tree-ssa-phiopt.c (minmax_replacement): Turn EQ/NE compares of extreme values to ordered comparisons. * gcc.dg/tree-ssa/phi-opt-20.c: New testcase. From-SVN: r265909 --- gcc/ChangeLog | 6 ++++++ gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/gcc.dg/tree-ssa/phi-opt-20.c | 25 +++++++++++++++++++++++++ gcc/tree-ssa-phiopt.c | 25 ++++++++++++++++++++++--- 4 files changed, 58 insertions(+), 3 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-20.c (limited to 'gcc') diff --git a/gcc/ChangeLog b/gcc/ChangeLog index decc5a0..270180f 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2018-11-08 Richard Biener + + PR tree-optimization/87913 + * tree-ssa-phiopt.c (minmax_replacement): Turn EQ/NE compares + of extreme values to ordered comparisons. + 2018-11-07 Sandra Loosemore PR middle-end/42726 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index e719c31..5edc17e 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2018-11-08 Richard Biener + + PR tree-optimization/87913 + * gcc.dg/tree-ssa/phi-opt-20.c: New testcase. + 2018-11-08 Chenghua Xu * gcc.target/mips/mips.exp (mips-dg-options): diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-20.c b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-20.c new file mode 100644 index 0000000..c310308 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-20.c @@ -0,0 +1,25 @@ +/* { dg-do compile } */ +/* { dg-options "-O -fdump-tree-phiopt1" } */ + +unsigned int f(unsigned int num) +{ + return num < 1 ? 1 : num; +} + +unsigned int g(unsigned int num) +{ + return num > (unsigned)__INT_MAX__ * 2 ? (unsigned)__INT_MAX__ * 2 : num; +} + +int h(int num) +{ + return num < -__INT_MAX__ ? -__INT_MAX__ : num; +} + +int i(int num) +{ + return num > __INT_MAX__-1 ? __INT_MAX__-1 : num; +} + +/* { dg-final { scan-tree-dump-times "MAX_EXPR" 2 "phiopt1" } } */ +/* { dg-final { scan-tree-dump-times "MIN_EXPR" 2 "phiopt1" } } */ diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c index 0784510..64039e2 100644 --- a/gcc/tree-ssa-phiopt.c +++ b/gcc/tree-ssa-phiopt.c @@ -1204,7 +1204,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb, edge e0, edge e1, gimple *phi, tree arg0, tree arg1) { - tree result, type; + tree result, type, rhs; gcond *cond; gassign *new_stmt; edge true_edge, false_edge; @@ -1220,6 +1220,25 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb, cond = as_a (last_stmt (cond_bb)); cmp = gimple_cond_code (cond); + rhs = gimple_cond_rhs (cond); + + /* Turn EQ/NE of extreme values to order comparisons. */ + if ((cmp == NE_EXPR || cmp == EQ_EXPR) + && TREE_CODE (rhs) == INTEGER_CST) + { + if (wi::eq_p (wi::to_wide (rhs), wi::min_value (TREE_TYPE (rhs)))) + { + cmp = (cmp == EQ_EXPR) ? LT_EXPR : GE_EXPR; + rhs = wide_int_to_tree (TREE_TYPE (rhs), + wi::min_value (TREE_TYPE (rhs)) + 1); + } + else if (wi::eq_p (wi::to_wide (rhs), wi::max_value (TREE_TYPE (rhs)))) + { + cmp = (cmp == EQ_EXPR) ? GT_EXPR : LE_EXPR; + rhs = wide_int_to_tree (TREE_TYPE (rhs), + wi::max_value (TREE_TYPE (rhs)) - 1); + } + } /* This transformation is only valid for order comparisons. Record which operand is smaller/larger if the result of the comparison is true. */ @@ -1228,7 +1247,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb, if (cmp == LT_EXPR || cmp == LE_EXPR) { smaller = gimple_cond_lhs (cond); - larger = gimple_cond_rhs (cond); + larger = rhs; /* If we have smaller < CST it is equivalent to smaller <= CST-1. Likewise smaller <= CST is equivalent to smaller < CST+1. */ if (TREE_CODE (larger) == INTEGER_CST) @@ -1255,7 +1274,7 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb, } else if (cmp == GT_EXPR || cmp == GE_EXPR) { - smaller = gimple_cond_rhs (cond); + smaller = rhs; larger = gimple_cond_lhs (cond); /* If we have larger > CST it is equivalent to larger >= CST+1. Likewise larger >= CST is equivalent to larger > CST-1. */ -- cgit v1.1