[PATCH] Fix PR30172, some folding of complex expressions
Richard Guenther
rguenther@suse.de
Wed Dec 13 16:21:00 GMT 2006
This adds the capability to fold z * +-I and z1 + z2 in case the real/imag
parts of z1/z2 are zero. This helps constructing complex constants such
as _Complex c = 5.0 + x*1.i but unfortunately only in cases we can ignore
(signalling) NaNs and signed zeros.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
Will apply to mainline later.
Richard.
2006-12-13 Richard Guenther <rguenther@suse.de>
PR middle-end/30172
* fold-const.c (fold_binary): Fold __complex__ ( x, 0 )
+ __complex__ ( 0, y ) to __complex__ ( x, y ).
Fold __complex__ (x, y) * +-I to __complex__ (-+y, +-x).
* gcc.dg/pr30172-1.c: New testcase.
Index: fold-const.c
===================================================================
*** fold-const.c (revision 119828)
--- fold-const.c (working copy)
*************** fold_binary (enum tree_code code, tree t
*** 8729,8734 ****
--- 8823,8863 ----
fold_convert (type, tem));
}
+ /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
+ to __complex__ ( x, y ). This is not the same for SNaNs or
+ if singed zeros are involved. */
+ if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
+ && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg0)))
+ && COMPLEX_FLOAT_TYPE_P (TREE_TYPE (arg0)))
+ {
+ tree rtype = TREE_TYPE (TREE_TYPE (arg0));
+ tree arg0r = fold_unary (REALPART_EXPR, rtype, arg0);
+ tree arg0i = fold_unary (IMAGPART_EXPR, rtype, arg0);
+ bool arg0rz = false, arg0iz = false;
+ if ((arg0r && (arg0rz = real_zerop (arg0r)))
+ || (arg0i && (arg0iz = real_zerop (arg0i))))
+ {
+ tree arg1r = fold_unary (REALPART_EXPR, rtype, arg1);
+ tree arg1i = fold_unary (IMAGPART_EXPR, rtype, arg1);
+ if (arg0rz && arg1i && real_zerop (arg1i))
+ {
+ tree rp = arg1r ? arg1r
+ : build1 (REALPART_EXPR, rtype, arg1);
+ tree ip = arg0i ? arg0i
+ : build1 (IMAGPART_EXPR, rtype, arg0);
+ return fold_build2 (COMPLEX_EXPR, type, rp, ip);
+ }
+ else if (arg0iz && arg1r && real_zerop (arg1r))
+ {
+ tree rp = arg0r ? arg0r
+ : build1 (REALPART_EXPR, rtype, arg0);
+ tree ip = arg1i ? arg1i
+ : build1 (IMAGPART_EXPR, rtype, arg1);
+ return fold_build2 (COMPLEX_EXPR, type, rp, ip);
+ }
+ }
+ }
+
if (flag_unsafe_math_optimizations
&& (TREE_CODE (arg0) == RDIV_EXPR || TREE_CODE (arg0) == MULT_EXPR)
&& (TREE_CODE (arg1) == RDIV_EXPR || TREE_CODE (arg1) == MULT_EXPR)
*************** fold_binary (enum tree_code code, tree t
*** 9181,9186 ****
--- 9310,9337 ----
}
}
+ /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
+ This is not the same for NaNs or if singed zeros are
+ involved. */
+ if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))
+ && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg0)))
+ && COMPLEX_FLOAT_TYPE_P (TREE_TYPE (arg0))
+ && TREE_CODE (arg1) == COMPLEX_CST
+ && real_zerop (TREE_REALPART (arg1)))
+ {
+ tree rtype = TREE_TYPE (TREE_TYPE (arg0));
+ if (real_onep (TREE_IMAGPART (arg1)))
+ return fold_build2 (COMPLEX_EXPR, type,
+ negate_expr (fold_build1 (IMAGPART_EXPR,
+ rtype, arg0)),
+ fold_build1 (REALPART_EXPR, rtype, arg0));
+ else if (real_minus_onep (TREE_IMAGPART (arg1)))
+ return fold_build2 (COMPLEX_EXPR, type,
+ fold_build1 (IMAGPART_EXPR, rtype, arg0),
+ negate_expr (fold_build1 (REALPART_EXPR,
+ rtype, arg0)));
+ }
+
/* Optimize z * conj(z) for floating point complex numbers.
Guarded by flag_unsafe_math_optimizations as non-finite
imaginary components don't produce scalar results. */
Index: testsuite/gcc.dg/pr30172-1.c
===================================================================
*** testsuite/gcc.dg/pr30172-1.c (revision 0)
--- testsuite/gcc.dg/pr30172-1.c (revision 0)
***************
*** 0 ****
--- 1,15 ----
+ /* { dg-do compile } */
+ /* { dg-options "-funsafe-math-optimizations -ffinite-math-only -fdump-tree-gimple" } */
+
+ _Complex double test1 (double x) { return x + 1.i; }
+ _Complex double test2 (double x) { return 1 + x * 1.i; }
+ _Complex double test3 (double x, double y) { return x + y * 1.i; }
+ _Complex double test4 (double x, double y) { return (x + y * 1.i) * 1.i; }
+ _Complex double test5 (double x, double y) { return (x + y * 1.i) * -1.i; }
+
+ /* { dg-final { scan-tree-dump "COMPLEX_EXPR <x, 1.0e\\+0>" "gimple" } } */
+ /* { dg-final { scan-tree-dump "COMPLEX_EXPR <1.0e\\+0, x>" "gimple" } } */
+ /* { dg-final { scan-tree-dump "COMPLEX_EXPR <x, y>" "gimple" } } */
+ /* { dg-final { scan-tree-dump "D.* = -y;\n.*COMPLEX_EXPR <D.*, x>" "gimple" } } */
+ /* { dg-final { scan-tree-dump "D.* = -x;\n.*COMPLEX_EXPR <y, D.*>" "gimple" } } */
+ /* { dg-final { cleanup-tree-dump "original" } } */
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