[Bug tree-optimization/114025] New: Seeming missing frange based optimizations

[Bug tree-optimization/114025] New: Seeming missing frange based optimizations

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114025

            Bug ID: 114025
           Summary: Seeming missing frange based optimizations
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Take:
```
#include <algorithm>
#include <stdexcept>

#if 1
#define AINLINE
#else
#define AINLINE [[gnu::always_inline]] inline
#endif

class TestClass
{
public:
    AINLINE void SetValue(float value);

private:
    float m_Value;
};

AINLINE
void TestClass::SetValue(float value)
{
    if (value >= 0.0f && value <= 100.0f) {
        m_Value = value;
    }
    else {
        throw std::out_of_range("Value must be [0, 100].");
    }
}

void TestFunc(TestClass& t, float value)
{
    value = std::clamp(value, 30.0f, 50.0f);
    // When TestClass::SetValue is inlined, the exception throwing code is not
eliminated.
    // Given that at this point we can prove that 'value' lies in the range
[30.0f, 50.0f] well within the range required by the setter function, we can
rid the not taken paths of code.
    t.SetValue(value);
}


```

at `-O3 -ffinite-math-only` when AINLINE is declared as nothing, TestFunc is
not always to just the clamp, but if we define it to be `inline` with
always_inline, then it is optimized to clamp. as far as I can tell the IR in
VRP1 is not able to handle correctly put the frange in for some of the SSA_NAME
and so `value >= 0.0f && value <= 100.0f` is not optimized away.