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| author | Iain Buclaw <ibuclaw@gdcproject.org> | 2022-12-10 17:17:35 +0100 |
|---|---|---|
| committer | Iain Buclaw <ibuclaw@gdcproject.org> | 2022-12-11 14:46:59 +0100 |
| commit | cc7f509d3c0b3ab63891cf7ca2def0fdfb3642c4 (patch) | |
| tree | 0644114399957ea67926b08ab5fe87d3b99bbe76 | |
| parent | d13b86f932ff7b9d8f41483fd869c637b67d4dec (diff) | |
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d: Expand bsr intrinsic as `clz(arg) ^ (argsize - 1)'
As well as removing unnecessary casts, this results in less temporaries
being generated during the initial gimple lowering pass. Otherwise the
code generated is identical to the former intrinsic expansion.
gcc/d/ChangeLog:
* intrinsics.cc (expand_intrinsic_bsf): Fix comment.
(expand_intrinsic_bsr): Use BIT_XOR_EXPR instead of MINUS_EXPR.
| -rw-r--r-- | gcc/d/intrinsics.cc | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/gcc/d/intrinsics.cc b/gcc/d/intrinsics.cc index 6d9f74a..46380e5 100644 --- a/gcc/d/intrinsics.cc +++ b/gcc/d/intrinsics.cc @@ -525,7 +525,7 @@ call_builtin_fn (tree callexp, built_in_function code, int n, ...) static tree expand_intrinsic_bsf (tree callexp) { - /* The bsr() intrinsic gets turned into __builtin_ctz(arg). + /* The bsf() intrinsic gets turned into __builtin_ctz(arg). The return value is supposed to be undefined if arg is zero. */ tree arg = CALL_EXPR_ARG (callexp, 0); int argsize = TYPE_PRECISION (TREE_TYPE (arg)); @@ -554,11 +554,11 @@ expand_intrinsic_bsf (tree callexp) static tree expand_intrinsic_bsr (tree callexp) { - /* The bsr() intrinsic gets turned into (size - 1) - __builtin_clz(arg). + /* The bsr() intrinsic gets turned into __builtin_clz(arg) ^ (size - 1). The return value is supposed to be undefined if arg is zero. */ tree arg = CALL_EXPR_ARG (callexp, 0); - tree type = TREE_TYPE (arg); - int argsize = TYPE_PRECISION (type); + tree type = TREE_TYPE (callexp); + int argsize = TYPE_PRECISION (TREE_TYPE (arg)); /* Which variant of __builtin_clz* should we call? */ built_in_function code = (argsize <= INT_TYPE_SIZE) ? BUILT_IN_CLZ @@ -570,13 +570,8 @@ expand_intrinsic_bsr (tree callexp) tree result = call_builtin_fn (callexp, code, 1, arg); - /* Handle int -> long conversions. */ - if (TREE_TYPE (result) != type) - result = fold_convert (type, result); - - result = fold_build2 (MINUS_EXPR, type, - build_integer_cst (argsize - 1, type), result); - return fold_convert (TREE_TYPE (callexp), result); + return fold_build2 (BIT_XOR_EXPR, type, result, + build_integer_cst (argsize - 1, type)); } /* Expand a front-end intrinsic call to INTRINSIC, which is either a call to |