commit c890c68e2862980731e95cb4b7982f10b29109b7
Author: Kyrylo Tkachov <kyrylo.tkachov@arm.com>
Date: Fri Nov 20 09:13:04 2015 +0000
[ifcvt] PR rtl-optimization/68435 Allow (c ? x++ : x--) form
@@ -2210,7 +2210,10 @@ noce_try_cmove_arith (struct noce_if_info *if_info)
if (tmp_b && then_bb)
{
FOR_BB_INSNS (then_bb, tmp_insn)
- if (modified_in_p (orig_b, tmp_insn))
+ /* Don't check inside insn_a. We will have changed it to emit_a
+ with a destination that doesn't conflict. */
+ if (!(insn_a && tmp_insn == insn_a)
+ && modified_in_p (orig_b, tmp_insn))
{
modified_in_a = true;
break;
@@ -2223,7 +2226,10 @@ noce_try_cmove_arith (struct noce_if_info *if_info)
if (tmp_b && else_bb)
{
FOR_BB_INSNS (else_bb, tmp_insn)
- if (modified_in_p (orig_a, tmp_insn))
+ /* Don't check inside insn_b. We will have changed it to emit_b
+ with a destination that doesn't conflict. */
+ if (!(insn_b && tmp_insn == insn_b)
+ && modified_in_p (orig_a, tmp_insn))
{
modified_in_b = true;
break;
new file mode 100644
@@ -0,0 +1,52 @@
+/* { dg-do compile { target aarch64*-*-* x86_64-*-* } } */
+/* { dg-options "-fdump-rtl-ce1 -O2 -w" } */
+
+typedef struct cpp_reader cpp_reader;
+enum cpp_ttype
+{
+ CPP_EQ =
+ 0, CPP_NOT, CPP_GREATER, CPP_LESS, CPP_PLUS, CPP_MINUS, CPP_MULT, CPP_DIV,
+ CPP_MOD, CPP_AND, CPP_OR, CPP_XOR, CPP_RSHIFT, CPP_LSHIFT, CPP_MIN,
+ CPP_MAX, CPP_COMPL, CPP_AND_AND, CPP_OR_OR, CPP_QUERY, CPP_COLON,
+ CPP_COMMA, CPP_OPEN_PAREN, CPP_CLOSE_PAREN, CPP_EQ_EQ, CPP_NOT_EQ,
+ CPP_GREATER_EQ, CPP_LESS_EQ, CPP_PLUS_EQ, CPP_MINUS_EQ, CPP_MULT_EQ,
+ CPP_DIV_EQ, CPP_MOD_EQ, CPP_AND_EQ, CPP_OR_EQ, CPP_XOR_EQ, CPP_RSHIFT_EQ,
+ CPP_LSHIFT_EQ, CPP_MIN_EQ, CPP_MAX_EQ, CPP_HASH, CPP_PASTE,
+ CPP_OPEN_SQUARE, CPP_CLOSE_SQUARE, CPP_OPEN_BRACE, CPP_CLOSE_BRACE,
+ CPP_SEMICOLON, CPP_ELLIPSIS, CPP_PLUS_PLUS, CPP_MINUS_MINUS, CPP_DEREF,
+ CPP_DOT, CPP_SCOPE, CPP_DEREF_STAR, CPP_DOT_STAR, CPP_ATSIGN, CPP_NAME,
+ CPP_NUMBER, CPP_CHAR, CPP_WCHAR, CPP_OTHER, CPP_STRING, CPP_WSTRING,
+ CPP_HEADER_NAME, CPP_COMMENT, CPP_MACRO_ARG, CPP_PADDING, CPP_EOF,
+};
+
+static struct op lex (cpp_reader *, int);
+
+struct op
+{
+ enum cpp_ttype op;
+ long value;
+};
+
+int
+_cpp_parse_expr (pfile)
+{
+ struct op init_stack[20];
+ struct op *stack = init_stack;
+ struct op *top = stack + 1;
+ int skip_evaluation = 0;
+ for (;;)
+ {
+ struct op op;
+ op = lex (pfile, skip_evaluation);
+ switch (op.op)
+ {
+ case CPP_OR_OR:
+ if (top->value)
+ skip_evaluation++;
+ else
+ skip_evaluation--;
+ }
+ }
+}
+
+/* { dg-final { scan-rtl-dump "2 true changes made" "ce1" } } */
Hi all, In this PR we fail to if-convert a case where in the expression x = c ? a : b; 'a' and 'b' are something like x + 1 and x - 1. So x appears in a and b. The code that checks that nothing from the else block modifies the registers used in a rejects this case. It should accept when the modification is in the last insn of the block i.e. insn_a or insn_b in the language of noce_try_cmove_arith because we will not be emitting insn_a and insn_b verbatim, but rather their modified versions emit_a and emit_b that have had their destinations modified to fresh pseudos, so no conflicts will arise. Bootstrapped and tested on arm, aarch64, x86_64. This improved if-conversion opportunities a bit across SPEC2006, not so much as to make a difference, but definitely a small improvement. Ok for trunk? Thanks, Kyrill 2015-11-23 Kyrylo Tkachov <kyrylo.tkachov@arm.com> PR rtl-optimization/68435 * ifcvt.c (noce_try_cmove_arith): Skip final insn when checking for clonflicts between a, b and the set destinations. 2015-11-23 Kyrylo Tkachov <kyrylo.tkachov@arm.com> PR rtl-optimization/68435 * gcc.dg/pr68435.c: New test.