[Bug tree-optimization/41442] New: missed optimization for boolean expression

["carrot at google dot com" <gcc-bugzilla at gcc dot gnu dot org>]

The boolean expression ((p1->next && !p2->next) || p2->next) can be simplified
as (p1->next || p2->next), but gcc failed to detect this.


The attached source code is an example, compile it with options -Os
-march=armv5te -mthumb, I got

        push    {lr}
        ldr     r3, [r0]    
        cmp     r3, #0      
        beq     .L2         
        ldr     r3, [r1]    // redundant load and comparison
        mov     r0, #0      
        cmp     r3, #0      //
        beq     .L3         // can branch to L3 directly
.L2:
        ldr     r0, [r1]
        neg     r3, r0
        adc     r0, r0, r3
.L3:
        @ sp needed for prologue
        pop     {pc}


-- 
           Summary: missed optimization for boolean expression
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: carrot at google dot com
 GCC build triplet: i686-linux
  GCC host triplet: i686-linux
GCC target triplet: arm-eabi


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41442