@@ -1358,6 +1358,20 @@ static int simplify_associative_binop(struct instruction *insn)
return REPEAT_CSE;
}
+static int simplify_sub(struct instruction *insn)
+{
+ pseudo_t src2 = insn->src2;
+ struct instruction *def;
+
+ switch (DEF_OPCODE(def, src2)) {
+ case OP_NEG: // (x - -y) --> (x + y)
+ insn->opcode = OP_ADD;
+ return replace_pseudo(insn, &insn->src2, def->src);
+ }
+
+ return 0;
+}
+
static int simplify_constant_unop(struct instruction *insn)
{
long long val = insn->src1->value;
@@ -1818,8 +1832,8 @@ int simplify_instruction(struct instruction *insn)
}
switch (insn->opcode) {
+ case OP_SUB: return simplify_sub(insn);
case OP_ADD:
- case OP_SUB:
case OP_MUL:
case OP_AND:
case OP_OR:
@@ -3,7 +3,6 @@ int sub_neg(int x, int y) { return x - -y; }
/*
* check-name: simplify-sub-neg
* check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
*
* check-output-ignore
* check-output-contains: add\\..*%arg., %arg.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> --- simplify.c | 16 +++++++++++++++- validation/optim/simplify-sub-neg.c | 1 - 2 files changed, 15 insertions(+), 2 deletions(-)