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riscv-gcc-1
Commit 6cb70f0c by Jim Wilson
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(build_binary_op): Can shorten shift only if shift count 

is less than size in bits of arg0.

From-SVN: r8528
parent 03f36098
Showing with 4 additions and 0 deletions
gcc/c-typeck.c
...@@ -2391,6 +2391,10 @@ build_binary_op (code, orig_op0, orig_op1, convert_p) ...@@ -2391,6 +2391,10 @@ build_binary_op (code, orig_op0, orig_op1, convert_p)
unsigned_arg = TREE_UNSIGNED (TREE_TYPE (op0)); unsigned_arg = TREE_UNSIGNED (TREE_TYPE (op0));
if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type) if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
/* We can shorten only if the shift count is less than the
number of bits in the smaller type size. */
&& TREE_INT_CST_HIGH (op1) == 0
&& TYPE_PRECISION (TREE_TYPE (arg0)) > TREE_INT_CST_LOW (op1)
/* If arg is sign-extended and then unsigned-shifted, /* If arg is sign-extended and then unsigned-shifted,
we can simulate this with a signed shift in arg's type we can simulate this with a signed shift in arg's type
only if the extended result is at least twice as wide only if the extended result is at least twice as wide
......
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