Strange behavior in C when comparing integers

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This problem is encountered in my mac environment where the gcc version is shown below:

Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 7.0.2 (clang-700.1.81)
Target: x86_64-apple-darwin14.5.0
Thread model: posix

The code segment is from one of the function.

int someFunction(int x, int n) {
    int TMin_n = -(1 << (n-1));
    int TMax_n = (1 << (n-1)) - 1;
    int a = -2147483648;
    printf("%s\n", x == a ? "true" : "false");      // true
    printf("%s\n", x <= TMax_n ? "true" : "false"); // false
    printf("%s\n", a <= TMax_n ? "true" : "false"); // true
    printf("%d %d %d\n", TMin_n, x, TMax_n);        // -2147483648 -2147483648 2147483647
    return 0;
}

a is equal to x, but why they have different behavior when comparing to TMax_n?

UPDATE:

all the data types in this code segment is int.

UPDATE2:

Thanks everyone. I just tried the same code on an ubuntu machine and that works fine. It only stuck on my MAC.Seems that it is a problem related with the compiler.

clang c
2 Answers
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