diff options
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index b8c080c..a4f0d66 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -7358,6 +7358,10 @@ force_to_mode (rtx x, enum machine_mode mode, unsigned HOST_WIDE_INT mask, return force_to_mode (SUBREG_REG (x), mode, mask, next_select); break; + case TRUNCATE: + /* Similarly for a truncate. */ + return force_to_mode (XEXP (x, 0), mode, mask, next_select); + case AND: /* If this is an AND with a constant, convert it into an AND whose constant is the AND of that constant with MASK. If it @@ -7502,12 +7506,20 @@ force_to_mode (rtx x, enum machine_mode mode, unsigned HOST_WIDE_INT mask, /* For most binary operations, just propagate into the operation and change the mode if we have an operation of that mode. */ - op0 = gen_lowpart_or_truncate (op_mode, - force_to_mode (XEXP (x, 0), mode, mask, - next_select)); - op1 = gen_lowpart_or_truncate (op_mode, - force_to_mode (XEXP (x, 1), mode, mask, - next_select)); + op0 = force_to_mode (XEXP (x, 0), mode, mask, next_select); + op1 = force_to_mode (XEXP (x, 1), mode, mask, next_select); + + /* If we ended up truncating both operands, truncate the result of the + operation instead. */ + if (GET_CODE (op0) == TRUNCATE + && GET_CODE (op1) == TRUNCATE) + { + op0 = XEXP (op0, 0); + op1 = XEXP (op1, 0); + } + + op0 = gen_lowpart_or_truncate (op_mode, op0); + op1 = gen_lowpart_or_truncate (op_mode, op1); if (op_mode != GET_MODE (x) || op0 != XEXP (x, 0) || op1 != XEXP (x, 1)) x = simplify_gen_binary (code, op_mode, op0, op1); |