[PATCH] Vectorize if-converted loop

[Devang Patel <dpatel at apple dot com>]

This patch enables vectorization of if-converted loops.

Now following loop is auto-vectorized!

  for (i = 0; i < 16; i++)
      A[i] = ( A[i] >= MAX ? MAX : 0);

This patch adds new routine vectorizable_select() to handle above loop. 
It uses existing APIs to create vector operands from scalar operands. 
Vectorized cond expr uses new VEC_COND_EXPR tree node.

VEC_COND_EXPR tree node is expanded using vcond_gen_code optab.

	http://gcc.gnu.org/ml/gcc-patches/2004-09/msg01689.html

Here expand_vec_cond_expr() is responsible for expanding VEC_COND_EXPR. 
expand_vec_cond_expr_p() is used by vectorizer to check vector 
conditional operation support on target. expand_vec_cond_expr() expands 
operands using standard expand_expr(). It uses is compare_from_rtx() to 
get comparison rtx for condition. It is handed over, along with 
operands rtx to vcond<mode> pattern.

Earlier I posted  RS6000 patch to add vcond<mode> patterns.

	http://gcc.gnu.org/ml/gcc-patches/2004-09/msg01691.html

Here, vcond<mode> patterns use rs6000_emit_vector_cond_expr() to do the 
job. Appropriate vector compare insn index is selected based on 
condition code, destination mode and operand mode. Similarly vector 
select insn index is selected based on destination mode. Using these 
indexes and operands appropriate vector compare and select insns are 
emitted.

Bootstrapped and tested on powerpc-darwin.
DejaGNU and SPEC testing does not indicate any regression.
Bootstrapped on powerpc-darwin using -ftree-vectorize.

I am also including entire diff with all of these patches as ifc2.diff 
here.

OK?
Thank you,
-
Devang

2004-09-15  Devang Patel  <dpatel@apple.com>

        * tree-vectorizer.c (vectorizable_select): New function.
        (vect_is_simle_cond): New function.
        (vect_transform_stmt): Handle select_vec_info_type.
        (vect_analyze_operations): Same.
        * tree-vectorizer.h (stmt_vec_info_type): New entry 
select_vec_info_type.

testsuite:
        * gcc.dg/vect/vect-20040915-2.c:  New test.

Attachment: ifc2_fsf_mainline.6.0.diff
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Attachment: ifc2.diff
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