From 7b1d4ca6b5ad28ccf8e489c58fe99c00b1436bfb Mon Sep 17 00:00:00 2001 From: Luc Van Oostenryck Date: Wed, 13 Jan 2021 00:49:16 +0100 Subject: cmps: canonicalize SMIN/SMAX +- 1 --> EQ/NE Compares with SMIN + 1 or SMAX - 1 are equivalent to an equality testing. For example, (x < SMIN + 1) is the same as (x == SMIN). Canonicalize these to the equality testing since these are usually simpler to handle. Signed-off-by: Luc Van Oostenryck --- simplify.c | 8 ++++++++ validation/optim/canonical-cmpe-minmax.c | 1 - 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/simplify.c b/simplify.c index f7c6c68d..ad3adb11 100644 --- a/simplify.c +++ b/simplify.c @@ -1175,24 +1175,32 @@ static int simplify_compare_constant(struct instruction *insn, long long value) return replace_with_pseudo(insn, value_pseudo(0)); if (value == sign_mask(size)) // (x < SMAX) --> (x != SMAX) return replace_opcode(insn, OP_SET_NE); + if (value == sign_bit(size) + 1)// (x < SMIN + 1) --> (x == SMIN) + return replace_binop_value(insn, OP_SET_EQ, sign_bit(size)); break; case OP_SET_LE: if (value == sign_mask(size)) // (x <= SMAX) --> 1 return replace_with_pseudo(insn, value_pseudo(1)); if (value == sign_bit(size)) // (x <= SMIN) --> (x == SMIN) return replace_opcode(insn, OP_SET_EQ); + if (value == sign_mask(size) - 1) // (x <= SMAX - 1) --> (x != SMAX) + return replace_binop_value(insn, OP_SET_NE, sign_mask(size)); break; case OP_SET_GE: if (value == sign_bit(size)) // (x >= SMIN) --> 1 return replace_with_pseudo(insn, value_pseudo(1)); if (value == sign_mask(size)) // (x >= SMAX) --> (x == SMAX) return replace_opcode(insn, OP_SET_EQ); + if (value == sign_bit(size) + 1)// (x >= SMIN + 1) --> (x != SMIN) + return replace_binop_value(insn, OP_SET_NE, sign_bit(size)); break; case OP_SET_GT: if (value == sign_mask(size)) // (x > SMAX) --> 0 return replace_with_pseudo(insn, value_pseudo(0)); if (value == sign_bit(size)) // (x > SMIN) --> (x != SMIN) return replace_opcode(insn, OP_SET_NE); + if (value == sign_mask(size) - 1) // (x > SMAX - 1) --> (x == SMAX) + return replace_binop_value(insn, OP_SET_EQ, sign_mask(size)); break; case OP_SET_B: diff --git a/validation/optim/canonical-cmpe-minmax.c b/validation/optim/canonical-cmpe-minmax.c index c7281924..32b27243 100644 --- a/validation/optim/canonical-cmpe-minmax.c +++ b/validation/optim/canonical-cmpe-minmax.c @@ -10,7 +10,6 @@ int ge_smin(int a) { return (a >= (SMIN + 1)) == (a != SMIN); } /* * check-name: canonical-cmpe-minmax * check-command: test-linearize -Wno-decl $file - * check-known-to-fail * * check-output-ignore * check-output-returns: 1 -- cgit 1.2.3-korg