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| author | Richard Kenner <kenner@gcc.gnu.org> | 1993-11-19 18:24:20 -0500 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 1993-11-19 18:24:20 -0500 |
| commit | 2dd484ed8ede94cd8940bbdfd8fa3d41c812430c (patch) | |
| tree | 4dd7347c0739a0c602c80e2dc6f3e44902b18b27 /gcc/combine.c | |
| parent | 35fc1624acabf68663c05b029b75763bff8fd6ab (diff) | |
| download | gcc-2dd484ed8ede94cd8940bbdfd8fa3d41c812430c.zip gcc-2dd484ed8ede94cd8940bbdfd8fa3d41c812430c.tar.gz gcc-2dd484ed8ede94cd8940bbdfd8fa3d41c812430c.tar.bz2 | |
(force_to_mode): Don't allow sign-extension of constants when we are
narrowing things in an IOR or XOR.
From-SVN: r6117
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 1d22a13..86be74a 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -5790,6 +5790,14 @@ force_to_mode (x, mode, mask, reg) op1 = gen_lowpart_for_combine (op_mode, force_to_mode (XEXP (x, 1), mode, mask, reg)); + /* If OP1 is a CONST_INT and X is an IOR or XOR, clear bits outside + MASK since OP1 might have been sign-extended but we never want + to turn on extra bits, since combine might have previously relied + on them being off. */ + if (GET_CODE (op1) == CONST_INT && (code == IOR || code == XOR) + && (INTVAL (op1) & mask) != 0) + op1 = GEN_INT (INTVAL (op1) & mask); + if (op_mode != GET_MODE (x) || op0 != XEXP (x, 0) || op1 != XEXP (x, 1)) x = gen_binary (code, op_mode, op0, op1); break; |