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llvm-mirror/test/CodeGen/ARM/ifconv-kills.ll
Matthias Braun f96d183309 Remove kill flags after if conversion if necessary
When if converting something like:
true:
   ... = R0<kill>

false:
   ... = R0<kill>

then the instructions of the true block must not have a <kill> flag
anymore, as the instruction of the false block follow and do still read
the R0 value.
Specifically this patch determines the set of register live-in in the
false block (possibly after simulating the liveness changes of the
duplicated instructions). Each of these live-in registers mustn't be
killed.

llvm-svn: 192482
2013-10-11 19:04:37 +00:00

31 lines
877 B
LLVM

; RUN: llc < %s -march arm -mcpu swift -verify-machineinstrs
declare i32 @f(i32 %p0, i32 %p1)
define i32 @foo(i32* %ptr) {
entry:
%cmp = icmp ne i32* %ptr, null
br i1 %cmp, label %if.then, label %if.else
; present something which can be easily if-converted
if.then:
; %R0 should be killed here
%valt = load i32* %ptr, align 4
br label %return
if.else:
; %R0 should be killed here, however after if-conversion the %R0 kill
; has to be removed because if.then will follow after this and still
; read it.
%addr = getelementptr inbounds i32* %ptr, i32 4
%vale = load i32* %addr, align 4
br label %return
return:
%phival = phi i32 [ %valt, %if.then ], [ %vale, %if.else ]
; suggest to bring %phival/%valt/%vale into %R1 (because otherwise there
; will be no kills in if.then/if.else)
%retval = call i32 @f (i32 0, i32 %phival)
ret i32 %retval
}