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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/114009] [11/12/13/14 Regression] Missed
 optimization: (!a) * a => 0 when a=(a/2)*2
Date: Tue, 05 Mar 2024 13:02:03 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114009

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Is the regression marker added for the
r11-2550-gca2b8c082c4f16919071c9f8de8db0b33b54c405 change:
        movl    %edi, %eax
-       xorl    %edx, %edx
+       movl    $0, %edx
        shrl    $31, %eax
        addl    %edi, %eax
+       addl    $1, %edi
        andl    $-2, %eax
-       sete    %dl
-       imull   %edx, %eax
+       cmpl    $2, %edi
+       cmova   %edx, %eax
        movl    %eax, w(%rip)
        ret
or for the r12-5392-g527e54a431473cc497204226a21f2831d2375e66 change:
-       movl    %edi, %eax
-       movl    $0, %edx
-       shrl    $31, %eax
-       addl    %edi, %eax
-       addl    $1, %edi
-       andl    $-2, %eax
-       cmpl    $2, %edi
-       cmova   %edx, %eax
+       leal    1(%rdi), %eax
+       movl    %edi, %edx
+       cmpl    $2, %eax
+       setbe   %al
+       shrl    $31, %edx
+       addl    %edi, %edx
+       movzbl  %al, %eax
+       sarl    %edx
+       imull   %edx, %eax
+       addl    %eax, %eax
or both?  I don't think we ever optimized this without -fwrapv to just 0.=