Bug 4631 – const array literal rebuilt on every usage

Status
RESOLVED
Resolution
DUPLICATE
Severity
normal
Priority
P2
Component
dmd
Product
D
Version
D2
Platform
Other
OS
Windows
Creation time
2010-08-12T00:52:00Z
Last change time
2010-09-08T20:11:39Z
Keywords
performance, wrong-code
Assigned to
nobody
Creator
r.sagitario

Comments

Comment #0 by r.sagitario — 2010-08-12T00:52:32Z
This assertion in this code fails: module test; const int[] arr = [ 1, 2, 3 ]; void main() { assert(arr.ptr == arr.ptr); } Here's the assembly for main: __Dmain comdat assume CS:__Dmain L0: push EBX push ESI push 3 push 2 push 1 push 3 mov EAX,offset FLAT:_D12TypeInfo_xAi6__initZ push EAX call near ptr __d_arrayliteralT add ESP,014h mov ECX,EAX mov EBX,3 push ECX push 3 push 2 push 1 push 3 mov EDX,offset FLAT:_D12TypeInfo_xAi6__initZ push EDX call near ptr __d_arrayliteralT add ESP,014h mov ECX,EAX mov EAX,3 mov ESI,ECX pop ECX cmp ECX,ESI je L4E mov EAX,7 call near ptr _D4test8__assertFiZv L4E: xor EAX,EAX pop ESI pop EBX ret __Dmain ends The array literal is constructed on every use, even though the constant array is written to the _DATA segment of the object file. I tried increasing the array size if there is some threshold, but with about 50 elements it's still the same. using "const(int)[] arr = [ 1, 2, 3 ];" works as expected. This looks similar to bug 2237, but the code here works ok for D1 while bug 2237 is D1 only.
Comment #1 by dsimcha — 2010-09-08T20:11:39Z
*** This issue has been marked as a duplicate of issue 4298 ***