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From: tabasso@tabasoft.it To: gcc-gnats@gcc.gnu.org Subject: c/7888: wrong code produced by GCC 3.1 Date: Wed, 11 Sep 2002 08:06:00 -0000 [thread overview] Message-ID: <20020911150005.4313.qmail@sources.redhat.com> (raw) >Number: 7888 >Category: c >Synopsis: wrong code produced by GCC 3.1 >Confidential: no >Severity: serious >Priority: medium >Responsible: unassigned >State: open >Class: wrong-code >Submitter-Id: net >Arrival-Date: Wed Sep 11 08:06:00 PDT 2002 >Closed-Date: >Last-Modified: >Originator: Raul Tabasso >Release: gcc 3.1 >Organization: >Environment: MacOSX 1.2 with gcc 3.1 compiling with NO -o option >Description: The GCC compiler version 3.1 produce wrong code when declaring a register variable of type double. Suppressing the register statement avoids the problem. The register clause in line: "register double zero = 0" produce a wrong code when using this register variable in a statement like "*dblP++ = zero;" where "dblP" is a pointer to a double. The code will clear only the first 4 bytes and NOT 8 as it should be. >How-To-Repeat: // Code that cause the bug: void ClearBlock(void *blockP, int blockSize) { register double zero = 0; double *dblP = (double*)blockP; int step32 = blockSize / (sizeof(double) * 4); char *charP(char*)blockP; if (step32) { blockSize -= step32 * (sizeof(double) * 4); do { *dblP++ = zero; *dblP++ = zero; *dblP++ = zero; *dblP++ = zero; } while (--step32); charP = (char*)dblP; } if (blockSize) { do { *charP++ = 0; } while (--blockSize); } } >Fix: >Release-Note: >Audit-Trail: >Unformatted:
next reply other threads:[~2002-09-11 15:06 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-09-11 8:06 tabasso [this message] 2002-09-11 9:01 nathan 2002-09-12 2:36 Raul Tabasso 2002-09-12 5:42 nathan 2002-09-13 2:56 Raul Tabasso 2002-09-15 17:56 Andrew Pinski 2002-09-16 0:56 Nathan Sidwell
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