Commit 85eaf6c6 by Richard Biener Committed by Richard Biener

re PR target/87913 (max(n, 1) code generation)

2018-11-08  Richard Biener  <rguenther@suse.de>

	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
parent ab681385
2018-11-08 Richard Biener <rguenther@suse.de>
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 <sandra@codesourcery.com>
PR middle-end/42726
2018-11-08 Richard Biener <rguenther@suse.de>
PR tree-optimization/87913
* gcc.dg/tree-ssa/phi-opt-20.c: New testcase.
2018-11-08 Chenghua Xu <paul.hua.gm@gmail.com>
* gcc.target/mips/mips.exp (mips-dg-options):
......
/* { 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" } } */
......@@ -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 <gcond *> (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. */
......
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