mirrors/dmd
1
0
Fork 0
mirror of https://github.com/dlang/dmd.git synced 2025-04-26 13:10:12 +03:00
Code Issues Projects Releases Packages Wiki Activity Actions 5

Fix #21024 - Optimize x^^c expressions (#21082)

Browse source 
* Fix #21024 - Optimize x^^c expressions

Reason for the *magic* constraint c<8 on inlining x^^c:

https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/x86_64/fpu/e_powl.S;h=47f129f34d368d7c67b8e5f2462b36b0bebb7621;hb=HEAD#l136

* Fix poor assumption about expression state

* Restrict optimization to floating point expressions

* Generalize optimization to any scalar data type

* Fix segfault on x^^c where x is a single member anonymous enum

DMD segfaulted on compiling the unittests in std/algorithm/sorting.o, the
unittest that caused the segfault can be reduced to:

    enum real Two = 2.0;
    auto _ = Two^^3;

I'm not sure why copying the anonymous enum into a `const` variable causes
the compiler to segfault.

* Add tests to x^^c inlining optimization

* Fix missing type for e1 ^^ -1 to 1 / e1 rewrite

* Move rewrites from constant folding to expression semantic and restrict them to [-1, 2]

* Improve error message for the x^^2 rewrite.

Before:
    ex.d(4): Error: can implicitly convert expression `(const const(double) __powtmp2 = x + 5.0;) , __powtmp2 * ...` of type `double` to `int`
        int y = ( x + 5 ) ^^ 2;
                ^
and after:
    ex.d(4): Error: cannot implicitly convert expression `(x + 5.0) ^^ 2L` of type `double` to `int`
        int y = ( x + 5 ) ^^ 2;
                ^

* Update C++ frontend header to match change in `CommaExp`

* Address code review feedback

Co-authored-by: Dennis Korpel <dkorpel@gmail.com>

---------

Co-authored-by: Dennis Korpel <dkorpel@gmail.com>
This commit is contained in:
Fares A. Bakhit 2025-03-29 13:13:38 +02:00 • committed by GitHub
parent d65a100b6c
commit fa1f860e4b
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
7 changed files with 151 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

38
compiler/test/fail_compilation/powinline.d Normal file
View file

@ -0,0 +1,38 @@
/*
TEST_OUTPUT:
---
fail_compilation/powinline.d(25): Error: cannot implicitly convert expression `(a + 5.0) ^^ 2L` of type `double` to `int`
fail_compilation/powinline.d(26): Error: cannot implicitly convert expression `(1.0 / foo()) ^^ 2L` of type `double` to `int`
fail_compilation/powinline.d(31): Error: void has no value
fail_compilation/powinline.d(31): Error: incompatible types for `(5.0) * (bar())`: `double` and `void`
fail_compilation/powinline.d(37): Error: cannot modify `immutable` expression `a`
---
*/
double foo()
{
return 5.0;
}
void bar()
{
return;
}
void test1()
{
double a = 2.0;
int b = (a + 5.0) ^^ 2.0;
b = (1 / foo()) ^^ 2.0;
}
void test2()
{
double a = (5.0 * bar()) ^^ 2.0;
}
void test3()
{
immutable double a = 3.0;
(a ^^= 2.0) = 6;
}