[Bug tree-optimization/108804] New: missed vectorization in presence of conversion from uint64_t to float

[vincenzo.innocente at cern dot ch via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108804

            Bug ID: 108804
           Summary: missed vectorization in presence of conversion from
                    uint64_t to float
           Product: gcc
           Version: 12.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vincenzo.innocente at cern dot ch
  Target Milestone: ---

in the following code [1] foo does not vectorize, bar doos
compiled with -march=haswell -Ofast --no-math-errno -Wall
see
https://godbolt.org/z/E6xzfavxc

clang seems do do better

[1]
#include<cstdint>



uint64_t d[512];
//uint32_t f[1024];
float f[1024];

void foo() {
    for (int i=0; i<512; ++i) {
        uint64_t k = d[i];
        auto x  = (k & 0x007FFFFF) |  0x3F800000;
        k = k >> 23;
        auto y  = (k & 0x007FFFFF) |  0x3F800000;
        f[i]=x; f[128+i] = y;

    }    
}

void bar() {
    for (int i=0; i<512; ++i) {
        uint64_t k = d[i];
        uint32_t x  = (k & 0x007FFFFF);
        x |= 0x3F800000;
        uint32_t y  = k >> 23;
        y  = (y & 0x007FFFFF) |  0x3F800000;
        f[i]=x; f[128+i] = y;

    }  
}