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[XCore] Support functions returning more than 4 words.

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If a function returns a large struct by value return the first 4 words
in registers and the rest on the stack in a location reserved by the
caller. This is needed to support the xC language which supports
functions returning an arbitrary number of return values. This is
r202397 reapplied with a fix to avoid an uninitialized read of a member.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202414 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Richard Osborne
2014-02-27 17:47:54 +00:00
parent 870d997d8c
commit cc331c8f40
6 changed files with 160 additions and 26 deletions
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39
test/CodeGen/XCore/bigstructret.ll
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@@ -3,8 +3,8 @@
%0 = type { i32, i32, i32, i32 }
%1 = type { i32, i32, i32, i32, i32 }
; Structs of 4 words can be returned in registers
define internal fastcc %0 @ReturnBigStruct() nounwind readnone {
; Structs of 4 words are returned in registers
define internal %0 @ReturnBigStruct() nounwind readnone {
entry:
%0 = insertvalue %0 zeroinitializer, i32 12, 0
%1 = insertvalue %0 %0, i32 24, 1
@@ -19,8 +19,39 @@ entry:
; CHECK: ldc r3, 24601
; CHECK: retsp 0
; Structs bigger than 4 words are returned via a hidden hidden sret-parameter
define internal fastcc %1 @ReturnBigStruct2() nounwind readnone {
; Structs of more than 4 words are partially returned in memory so long as the
; function is not variadic.
define { i32, i32, i32, i32, i32} @f(i32, i32, i32, i32, i32) nounwind readnone {
; CHECK-LABEL: f:
; CHECK: ldc [[REGISTER:r[0-9]+]], 5
; CHECK-NEXT: stw [[REGISTER]], sp[2]
; CHECK-NEXT: retsp 0
body:
ret { i32, i32, i32, i32, i32} { i32 undef, i32 undef, i32 undef, i32 undef, i32 5}
}
@x = external global i32
@y = external global i32
; Check we call a function returning more than 4 words correctly.
define i32 @g() nounwind {
; CHECK-LABEL: g:
; CHECK: entsp 3
; CHECK: ldc [[REGISTER:r[0-9]+]], 0
; CHECK: stw [[REGISTER]], sp[1]
; CHECK: bl f
; CHECK-NEXT: ldw r0, sp[2]
; CHECK-NEXT: retsp 3
;
body:
%0 = call { i32, i32, i32, i32, i32 } @f(i32 0, i32 0, i32 0, i32 0, i32 0)
%1 = extractvalue { i32, i32, i32, i32, i32 } %0, 4
ret i32 %1
}
; Variadic functions return structs bigger than 4 words via a hidden
; sret-parameter
define internal %1 @ReturnBigStruct2(i32 %dummy, ...) nounwind readnone {
entry:
%0 = insertvalue %1 zeroinitializer, i32 12, 0
%1 = insertvalue %1 %0, i32 24, 1