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| author | Paolo Bonzini <bonzini@gnu.org> | 2016-11-28 13:21:02 +0000 |
|---|---|---|
| committer | Paolo Bonzini <bonzini@gcc.gnu.org> | 2016-11-28 13:21:02 +0000 |
| commit | 51a07549a93a00d5226635749a5eecf55f451984 (patch) | |
| tree | 3e830f40caac9290970b1efe2a864f5cfa0b7e27 /gcc/combine.c | |
| parent | 6383ff9f9e2b4fad5a0d7a76de5548b3255ea9a7 (diff) | |
| download | gcc-51a07549a93a00d5226635749a5eecf55f451984.zip gcc-51a07549a93a00d5226635749a5eecf55f451984.tar.gz gcc-51a07549a93a00d5226635749a5eecf55f451984.tar.bz2 | |
combine.c (simplify_if_then_else): Simplify IF_THEN_ELSE that isolates a single bit...
gcc:
* combine.c (simplify_if_then_else): Simplify IF_THEN_ELSE
that isolates a single bit, even if the condition involves
subregs.
From-SVN: r242917
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index ecf6741..45d4048 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -6522,14 +6522,22 @@ simplify_if_then_else (rtx x) simplify_shift_const (NULL_RTX, ASHIFT, mode, gen_lowpart (mode, XEXP (cond, 0)), i); - /* (IF_THEN_ELSE (NE REG 0) (0) (8)) is REG for nonzero_bits (REG) == 8. */ + /* (IF_THEN_ELSE (NE A 0) C1 0) is A or a zero-extend of A if the only + non-zero bit in A is C1. */ if (true_code == NE && XEXP (cond, 1) == const0_rtx && false_rtx == const0_rtx && CONST_INT_P (true_rtx) - && GET_MODE (XEXP (cond, 0)) == mode + && INTEGRAL_MODE_P (GET_MODE (XEXP (cond, 0))) && (UINTVAL (true_rtx) & GET_MODE_MASK (mode)) - == nonzero_bits (XEXP (cond, 0), mode) + == nonzero_bits (XEXP (cond, 0), GET_MODE (XEXP (cond, 0))) && (i = exact_log2 (UINTVAL (true_rtx) & GET_MODE_MASK (mode))) >= 0) - return XEXP (cond, 0); + { + rtx val = XEXP (cond, 0); + enum machine_mode val_mode = GET_MODE (val); + if (val_mode == mode) + return val; + else if (GET_MODE_PRECISION (val_mode) < GET_MODE_PRECISION (mode)) + return simplify_gen_unary (ZERO_EXTEND, mode, val, val_mode); + } return x; } |