Compiler Warning with Inline Assembly in C: advanced patterns on x86_64
I've looked through the documentation and I'm still confused about I'm having trouble with I'm working on a C program that requires inline assembly for performance optimization on an x86_64 architecture. However, I'm working with a compiler warning that I need to seem to resolve, and it's affecting my program's behavior. The warning I'm receiving is `warning: asm operand 0 probably doesn't match constraints` when I try to compile the following code: ```c #include <stdio.h> int main() { int a = 10; int b; __asm__ volatile ( "movl %[input], %%eax;\n" // Moving input to eax "addl $5, %%eax;\n" // Adding 5 "movl %%eax, %[output];\n" // Moving result to output : [output] "=r" (b) // Output operand : [input] "r" (a) // Input operand : "%eax" // Clobbered register ); printf("Result: %d\n", b); return 0; } ``` When I run the program, I expect `b` to equal 15, but instead, I'm getting 0. I've checked the inline assembly and the constraints, and everything seems correct. I even tried replacing the `movl` and `addl` instructions with simpler operations, but the scenario continues. I'm compiling with GCC 11.1.0 on Ubuntu 20.04, and I've also tried different optimization levels without any change in the results. Could this be an scenario with how I've defined my constraints, or is there something else going on? Any insights would be greatly appreciated! The project is a mobile app built with C. Any advice would be much appreciated. I've been using C for about a year now.