gcc-4.4 gave spurious "warning: array subscript is above array bounds"

[Edmund Grimley Evans]

Binary package hint: gcc-4.4

// This code gives a spurious
// "warning: array subscript is above array bounds"
// with gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-14ubuntu5)
// when compiled with: gcc -c -O2 -Wall

struct s { int a[100]; };

void f(struct s *ps, int i)
{
  int *a = ps->a;
  if (i >= 0x20000000 && i < 0x20000004)
    a[i - 0x20000000] = 0;
}

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: gcc-4.4 4.4.4-14ubuntu5
ProcVersionSignature: Ubuntu 2.6.35-980.1release9-omap4 2.6.35.3
Uname: Linux 2.6.35-980-omap4 armv7l
Architecture: armel
Date: Thu Mar 10 16:51:56 2011
ProcEnviron:
 LC_COLLATE=C
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: gcc-4.4