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llvm-project/llvm/test/CodeGen/ARM/2009-05-07-RegAllocLocal.ll

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Keep track of the last place a live virtreg was used. This allows us to add accurate kill markers, something the scavenger likes. Add some more tests from ARM that needed this. llvm-svn: 103521
2010-05-12 07:24:45 +08:00
; RUN: llc < %s -mtriple=armv5-unknown-linux-gnueabi -O0 -regalloc=fast
Fix pr4100. Do not remove no-op copies when they are dead. The register scavenger gets confused about register liveness if it doesn't see them. I'm not thrilled with this solution, but it only comes up when there are dead copies in the code, which is something that hopefully doesn't happen much. Here is what happens in pr4100: As shown in the following excerpt from the debug output of llc, the source of a move gets reloaded from the stack, inserting a new load instruction before the move. Since that source operand is a kill, the physical register is free to be reused for the destination of the move. The move ends up being a no-op, copying R3 to R3, so it is deleted. But, it leaves behind the load to reload %reg1028 into R3, and that load is not updated to show that it's destination operand (R3) is dead. The scavenger gets confused by that load because it thinks that R3 is live. Starting RegAlloc of: %reg1025<def,dead> = MOVr %reg1028<kill>, 14, %reg0, %reg0 Regs have values: Reloading %reg1028 into R3 Last use of R3[%reg1028], removing it from live set Assigning R3 to %reg1025 Register R3 [%reg1025] is never used, removing it from live set Alternative solutions might be either marking the load as dead, or zapping the load along with the no-op copy. I couldn't see an easy way to do either of those, though. llvm-svn: 71196
2009-05-08 07:47:03 +08:00
; PR4100
@.str = external constant [30 x i8] ; <[30 x i8]*> [#uses=1]
define i16 @fn16(i16 %arg0.0, <2 x i16> %arg1, i16 %arg2.0) nounwind {
entry:
store <2 x i16> %arg1, <2 x i16>* null
[opaque pointer type] Add textual IR support for explicit type parameter to the call instruction See r230786 and r230794 for similar changes to gep and load respectively. Call is a bit different because it often doesn't have a single explicit type - usually the type is deduced from the arguments, and just the return type is explicit. In those cases there's no need to change the IR. When that's not the case, the IR usually contains the pointer type of the first operand - but since typed pointers are going away, that representation is insufficient so I'm just stripping the "pointerness" of the explicit type away. This does make the IR a bit weird - it /sort of/ reads like the type of the first operand: "call void () %x(" but %x is actually of type "void ()*" and will eventually be just of type "ptr". But this seems not too bad and I don't think it would benefit from repeating the type ("void (), void () * %x(" and then eventually "void (), ptr %x(") as has been done with gep and load. This also has a side benefit: since the explicit type is no longer a pointer, there's no ambiguity between an explicit type and a function that returns a function pointer. Previously this case needed an explicit type (eg: a function returning a void() function was written as "call void () () * @x(" rather than "call void () * @x(" because of the ambiguity between a function returning a pointer to a void() function and a function returning void). No ambiguity means even function pointer return types can just be written alone, without writing the whole function's type. This leaves /only/ the varargs case where the explicit type is required. Given the special type syntax in call instructions, the regex-fu used for migration was a bit more involved in its own unique way (as every one of these is) so here it is. Use it in conjunction with the apply.sh script and associated find/xargs commands I've provided in rr230786 to migrate your out of tree tests. Do let me know if any of this doesn't cover your cases & we can iterate on a more general script/regexes to help others with out of tree tests. About 9 test cases couldn't be automatically migrated - half of those were functions returning function pointers, where I just had to manually delete the function argument types now that we didn't need an explicit function type there. The other half were typedefs of function types used in calls - just had to manually drop the * from those. import fileinput import sys import re pat = re.compile(r'((?:=|:|^|\s)call\s(?:[^@]*?))(\s*$|\s*(?:(?:\[\[[a-zA-Z0-9_]+\]\]|[@%](?:(")?[\\\?@a-zA-Z0-9_.]*?(?(3)"|)|{{.*}}))(?:\(|$)|undef|inttoptr|bitcast|null|asm).*$)') addrspace_end = re.compile(r"addrspace\(\d+\)\s*\*$") func_end = re.compile("(?:void.*|\)\s*)\*$") def conv(match, line): if not match or re.search(addrspace_end, match.group(1)) or not re.search(func_end, match.group(1)): return line return line[:match.start()] + match.group(1)[:match.group(1).rfind('*')].rstrip() + match.group(2) + line[match.end():] for line in sys.stdin: sys.stdout.write(conv(re.search(pat, line), line)) llvm-svn: 235145
2015-04-17 07:24:18 +08:00
%0 = call i32 (i8*, ...) @printf(i8* getelementptr ([30 x i8], [30 x i8]* @.str, i32 0, i32 0), i32 0) nounwind ; <i32> [#uses=0]
Fix pr4100. Do not remove no-op copies when they are dead. The register scavenger gets confused about register liveness if it doesn't see them. I'm not thrilled with this solution, but it only comes up when there are dead copies in the code, which is something that hopefully doesn't happen much. Here is what happens in pr4100: As shown in the following excerpt from the debug output of llc, the source of a move gets reloaded from the stack, inserting a new load instruction before the move. Since that source operand is a kill, the physical register is free to be reused for the destination of the move. The move ends up being a no-op, copying R3 to R3, so it is deleted. But, it leaves behind the load to reload %reg1028 into R3, and that load is not updated to show that it's destination operand (R3) is dead. The scavenger gets confused by that load because it thinks that R3 is live. Starting RegAlloc of: %reg1025<def,dead> = MOVr %reg1028<kill>, 14, %reg0, %reg0 Regs have values: Reloading %reg1028 into R3 Last use of R3[%reg1028], removing it from live set Assigning R3 to %reg1025 Register R3 [%reg1025] is never used, removing it from live set Alternative solutions might be either marking the load as dead, or zapping the load along with the no-op copy. I couldn't see an easy way to do either of those, though. llvm-svn: 71196
2009-05-08 07:47:03 +08:00
ret i16 0
}
declare i32 @printf(i8*, ...) nounwind