AArch64 assembler error in fcl-web under -O4 -CriotR

Original Reporter info from Mantis: CuriousKit @CuriousKit

• Reporter name: J. Gareth Moreton

Description:

When the trunk is built under the options "-O4 -CriotR", an assembler error is generated:

...
Writing Resource String Table file: fpweb.rsj
Assembling fpweb
Assembling webpage
Writing Resource String Table file: fphtml.rsj
Assembling fphtml
Compiling ./fcl-web/src/base/fpdatasetform.pp
Assembling fpdatasetform
fpdatasetform.pp(1281) Error: Error while assembling exitcode 1
fpdatasetform.pp(1281) Fatal: There were 2 errors compiling module, stopping
fcl-web/units/aarch64-linux/fpdatasetform.s: Assembler messages:
fcl-web/units/aarch64-linux/fpdatasetform.s:2598: Error: missing extend operator at operand 3 -- `adds x19,x0,w1'
Fatal: Compilation aborted

This error also occurs if -OoNOPEEPHOLE is specified, indicating that the bug is not located in the Peephole Optimizerr.

Steps to reproduce:

Build the trunk under an aarch64-linux platform OPT="-O4 -CriotR" (and -a if you want the assembly dumps) and observe the error when attempting to build the fcl-web package.

Additional information:

The culprit block of code in "fcl-web/units/aarch64-linux/fpdatasetform.s" is as follows (this block isn't modified by the Peephole Optimizer and appears the same under -OoNOPEEPHOLE):

.Lj361:

	movz	w23,1
	sxtw	x0,w22
	ldr	w1,[x26, 372]
	adds	x19,x0,w1 <=== Erroneous instruction
	b.vc	.Lj368
	bl	FPC_OVERFLOW
.Lj368:

Mantis conversion info:

• Mantis ID: 38840
• OS: Debian GNU/Linux (Raspberry Pi)
• OS Build: 10
• Build: r49298
• Platform: aarch64-linux
• Version: 3.3.1