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| author | Uros Bizjak <uros@gcc.gnu.org> | 2012-10-01 17:00:41 +0200 |
|---|---|---|
| committer | Uros Bizjak <uros@gcc.gnu.org> | 2012-10-01 17:00:41 +0200 |
| commit | 992103ad6991bfbd908d10b18b3fba28196ff7a8 (patch) | |
| tree | cc5f6d3ec972893a489639fb23536628899e340c /gcc/simplify-rtx.c | |
| parent | 4f39564266a2c44145e02cda4effd42a33cf66e9 (diff) | |
| download | gcc-992103ad6991bfbd908d10b18b3fba28196ff7a8.zip gcc-992103ad6991bfbd908d10b18b3fba28196ff7a8.tar.gz gcc-992103ad6991bfbd908d10b18b3fba28196ff7a8.tar.bz2 | |
re PR rtl-optimization/54457 ([x32] Fail to combine 64bit index + constant)
PR rtl-optimization/54457
* simplify-rtx.c (simplify_subreg):
Simplify (subreg:M (op:N ((x:N) (y:N)), 0)
to (op:M (subreg:M (x:N) 0) (subreg:M (x:N) 0)), where
the outer subreg is effectively a truncation to the original mode M.
testsuite/ChangeLog:
PR rtl-optimization/54457
* gcc.target/i386/pr54457.c: New test.
From-SVN: r191928
Diffstat (limited to 'gcc/simplify-rtx.c')
| -rw-r--r-- | gcc/simplify-rtx.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index aebe6bb..c3e8a0a 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -5724,6 +5724,28 @@ simplify_subreg (enum machine_mode outermode, rtx op, return CONST0_RTX (outermode); } + /* Simplify (subreg:SI (op:DI ((x:DI) (y:DI)), 0) + to (op:SI (subreg:SI (x:DI) 0) (subreg:SI (x:DI) 0)), where + the outer subreg is effectively a truncation to the original mode. */ + if ((GET_CODE (op) == PLUS + || GET_CODE (op) == MINUS + || GET_CODE (op) == MULT) + && SCALAR_INT_MODE_P (outermode) + && SCALAR_INT_MODE_P (innermode) + && GET_MODE_PRECISION (outermode) < GET_MODE_PRECISION (innermode) + && byte == subreg_lowpart_offset (outermode, innermode)) + { + rtx op0 = simplify_gen_subreg (outermode, XEXP (op, 0), + innermode, byte); + if (op0) + { + rtx op1 = simplify_gen_subreg (outermode, XEXP (op, 1), + innermode, byte); + if (op1) + return simplify_gen_binary (GET_CODE (op), outermode, op0, op1); + } + } + /* Simplify (subreg:QI (lshiftrt:SI (sign_extend:SI (x:QI)) C), 0) into to (ashiftrt:QI (x:QI) C), where C is a suitable small constant and the outer subreg is effectively a truncation to the original mode. */ |