Bug 12862 – [ICE] backend assertion (Internal error: backend/cg87.c 331) with inline, optimizing and floats

cat > bug.d << CODE struct FRect { float left, top, right, bottom; } void formatValue(float obj) { static void byRef(ref float a) {} byRef(obj); } void formatValue(FRect val) { formatValue(val.left); formatValue(val.top); } struct Foo { void bug() { formatValue(bounds); } @property FRect bounds() { if (&this !is null) return FRect(); else return FRect(); } } CODE dmd -c -O -inline bug.d ---- Internal error: backend/cg87.c 331 ---- The assertion is in STATIC code * makesure87(elem *e,unsigned offset,int i,unsigned flag) assert(_8087elems[i].e == NULL); Debug output for the assertion is _8087elems[0].e = 0x1050968, .offset = 8 Looks like a place in the floating point stack is still occupied by some older value. No idea how to fix this though.

I can't reproduce this on win32 or linux64

Mmh, the codegen assertion vanished with this commit (https://github.com/D-Programming-Language/dmd/commit/9efe7f74c2462e8743f5a479cd04f9be733be4b0). I reproduced another test case for the issue. cat > bug.d << CODE struct FPoint { float x, y; } struct FRect { float left, top, right, bottom; static FRect calcBounds(FPoint[] ) { return FRect(); } } struct Matrix { FRect mapRect(FRect src) { FPoint[] pts = new FPoint[](1); pts[0].x = src.left; pts[0].y = src.top; return FRect.calcBounds(pts); } } // TODO: FPoint -> Point!T struct Path { @property FRect bounds() { if (points.length) return FRect(); else return FRect(); } FPoint[] points; } void foo() { Matrix mat; Path path; mat.mapRect(path.bounds); } CODE The issues first appeared with dmd2.060 and seems to be triggered by assigning tym = TYucent to 16 byte structs that consist of either 4 floats or 2 doubles in elstruct (https://github.com/D-Programming-Language/dmd/blob/5cc1c812227440d199f265dec8fb976bea7ad943/src/backend/cgelem.c#L3077). I don't understand that code good enough to fix the issue though.

this works fine nowadays (git 7036b216dcb5d2b8394ae5c12324227c8ca47187), w or w/o -O -inline, -m32 or -m64.