diff options
Diffstat (limited to 'gcc/cse.c')
| -rw-r--r-- | gcc/cse.c | 49 |
1 files changed, 38 insertions, 11 deletions
@@ -4267,16 +4267,29 @@ fold_rtx (rtx x, rtx insn) enum rtx_code associate_code; rtx new_const; - if (y == 0 - || 0 == (inner_const - = equiv_constant (fold_rtx (XEXP (y, 1), 0))) - || GET_CODE (inner_const) != CONST_INT - /* If we have compiled a statement like - "if (x == (x & mask1))", and now are looking at - "x & mask2", we will have a case where the first operand - of Y is the same as our first operand. Unless we detect - this case, an infinite loop will result. */ - || XEXP (y, 0) == folded_arg0) + if (is_shift + && (INTVAL (const_arg1) >= GET_MODE_BITSIZE (mode) + || INTVAL (const_arg1) < 0)) + { + if (SHIFT_COUNT_TRUNCATED) + const_arg1 = GEN_INT (INTVAL (const_arg1) + & (GET_MODE_BITSIZE (mode) - 1)); + else + break; + } + + if (y == 0) + break; + inner_const = equiv_constant (fold_rtx (XEXP (y, 1), 0)); + if (!inner_const || GET_CODE (inner_const) != CONST_INT) + break; + + /* If we have compiled a statement like + "if (x == (x & mask1))", and now are looking at + "x & mask2", we will have a case where the first operand + of Y is the same as our first operand. Unless we detect + this case, an infinite loop will result. */ + if (XEXP (y, 0) == folded_arg0) break; /* Don't associate these operations if they are a PLUS with the @@ -4295,6 +4308,17 @@ fold_rtx (rtx x, rtx insn) && exact_log2 (- INTVAL (const_arg1)) >= 0))) break; + if (is_shift + && (INTVAL (inner_const) >= GET_MODE_BITSIZE (mode) + || INTVAL (inner_const) < 0)) + { + if (SHIFT_COUNT_TRUNCATED) + inner_const = GEN_INT (INTVAL (inner_const) + & (GET_MODE_BITSIZE (mode) - 1)); + else + break; + } + /* Compute the code used to compose the constants. For example, A-C1-C2 is A-(C1 + C2), so if CODE == MINUS, we want PLUS. */ @@ -4312,13 +4336,16 @@ fold_rtx (rtx x, rtx insn) shift on a machine that does a sign-extend as a pair of shifts. */ - if (is_shift && GET_CODE (new_const) == CONST_INT + if (is_shift + && GET_CODE (new_const) == CONST_INT && INTVAL (new_const) >= GET_MODE_BITSIZE (mode)) { /* As an exception, we can turn an ASHIFTRT of this form into a shift of the number of bits - 1. */ if (code == ASHIFTRT) new_const = GEN_INT (GET_MODE_BITSIZE (mode) - 1); + else if (!side_effects_p (XEXP (y, 0))) + return CONST0_RTX (mode); else break; } |