I just tried to compile package gsl-1.7-2 from Suse Linux with a recent GNU C compiler version 4.2 snapshot 20060121. The compiler snapshot said /home/dcb/gnu/42-20060121/results/bin/gcc -g -O3 -Wall -fmessage-length=0 -DHAVE_CONFIG_H -I. -I. -I.. -I.. -O2 -g -fmessage-length=0 -D_FORTIFY_SOURCE=2 -O3 -finline-limit=720 --param max-inline-insns-auto=160 -ffast-math -funroll-loops -fno-strict-aliasing -momit-leaf-frame-pointer -funit-at-a-time -ftree-vectorize -c bessel_Kn.c -fPIC -DPIC -o bessel_Kn.o bessel_Kn.c: In function sel_Kn.c:103: internal compiler error: in vect_recog_dot_prod_pattern, at tree-vect-patterns.c:246 Please submit a full bug report, with preprocessed source if appropriate. See <URL:http://gcc.gnu.org/bugs.html> for instructions. It seems that the flags -O2 -ffast-math -ftree-vectorize are required. Preprocessed source code attached.
Created attachment 10703 [details] c source code
Reducing.
Reduced testcase: double bessel_Kn_scaled_small_x(int n, double x) { int k; double y = 0.25 * x * x; double ex = exp(x); double k_term; double term1, sum1, ln_pre1; double term2, sum2, pre2; for(k=1; k<=n-1; k++) { k_term *= -y/(k * (n-k)); sum1 += k_term; } term1 = 0.5 * exp(ln_pre1) * sum1; return ex * (term1 + term2); }
Further reduced: double bessel_Kn_scaled_small_x(int n) { int k; double k_term, sum1; for(k=1; k<=n-1; k++) { k_term *= -1/(k * (n-k)); sum1 += k_term; } return sum1; }
Patch: Index: tree-vect-patterns.c =================================================================== --- tree-vect-patterns.c (revision 109954) +++ tree-vect-patterns.c (working copy) @@ -243,7 +243,8 @@ gcc_assert (stmt); stmt_vinfo = vinfo_for_stmt (stmt); gcc_assert (stmt_vinfo); - gcc_assert (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_loop_def); + if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_loop_def) + return NULL; expr = TREE_OPERAND (stmt, 1); if (TREE_CODE (expr) != MULT_EXPR) return NULL;
Patch posted: http://gcc.gnu.org/ml/gcc-patches/2006-01/msg01621.html
Subject: Bug 25911 Author: dorit Date: Sun Jan 29 16:50:05 2006 New Revision: 110377 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110377 Log: PR tree-opt/25911 * tree-vect-patterns.c (vect_recog_dot_prod_pattern): Change assert to an if check. Added: trunk/gcc/testsuite/gcc.dg/vect/fast-math-vect-pr25911.c Modified: trunk/gcc/ChangeLog trunk/gcc/testsuite/ChangeLog trunk/gcc/tree-vect-patterns.c
Fixed.