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llvm-project/llvm/test/Transforms/FixIrreducible/basic.ll

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Introduce fix-irreducible pass An irreducible SCC is one which has multiple "header" blocks, i.e., blocks with control-flow edges incident from outside the SCC. This pass converts an irreducible SCC into a natural loop by introducing a single new header block and redirecting all the edges on the original headers to this new block. This is a useful workaround for a limitation in the structurizer which, which produces incorrect control flow in the presence of irreducible regions. The AMDGPU backend provides an option to enable this pass before the structurizer, which may eventually be enabled by default. Reviewed By: nhaehnle Differential Revision: https://reviews.llvm.org/D77198 This restores commit 2ada8e2525dd2653f30c8696a27162a3b1647d66. Originally reverted with commit 44e09b59b869a91bf47d76e8bc569d9ee91ad145.
2020-04-15 17:35:51 +08:00
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -fix-irreducible -S | FileCheck %s -check-prefix=CHECK
[FixIrreducible][NewPM] Port -fix-irreducible to NPM In the NPM, a pass cannot depend on another non-analysis pass. So pin the test that tests that -lowerswitch is run automatically to legacy PM. Reviewed By: sameerds Differential Revision: https://reviews.llvm.org/D89051
2020-10-08 23:53:00 +08:00
; RUN: opt < %s -passes=fix-irreducible -S | FileCheck %s -check-prefix=CHECK
Introduce fix-irreducible pass An irreducible SCC is one which has multiple "header" blocks, i.e., blocks with control-flow edges incident from outside the SCC. This pass converts an irreducible SCC into a natural loop by introducing a single new header block and redirecting all the edges on the original headers to this new block. This is a useful workaround for a limitation in the structurizer which, which produces incorrect control flow in the presence of irreducible regions. The AMDGPU backend provides an option to enable this pass before the structurizer, which may eventually be enabled by default. Reviewed By: nhaehnle Differential Revision: https://reviews.llvm.org/D77198 This restores commit 2ada8e2525dd2653f30c8696a27162a3b1647d66. Originally reverted with commit 44e09b59b869a91bf47d76e8bc569d9ee91ad145.
2020-04-15 17:35:51 +08:00
define i32 @basic(i1 %PredEntry, i1 %PredLeft, i1 %PredRight, i32 %X, i32 %Y) {
; CHECK-LABEL: @basic(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[IRR_GUARD:%.*]]
; CHECK: left:
; CHECK-NEXT: [[L:%.*]] = add i32 [[L_PHI_MOVED:%.*]], 1
; CHECK-NEXT: br i1 [[PREDLEFT:%.*]], label [[IRR_GUARD]], label [[EXIT:%.*]]
; CHECK: right:
; CHECK-NEXT: br i1 [[PREDRIGHT:%.*]], label [[IRR_GUARD]], label [[EXIT]]
; CHECK: exit:
; CHECK-NEXT: [[Z:%.*]] = phi i32 [ [[L]], [[LEFT:%.*]] ], [ [[R_PHI_MOVED:%.*]], [[RIGHT:%.*]] ]
; CHECK-NEXT: ret i32 [[Z]]
; CHECK: irr.guard:
; CHECK-NEXT: [[GUARD_LEFT:%.*]] = phi i1 [ true, [[RIGHT]] ], [ [[PREDENTRY:%.*]], [[ENTRY:%.*]] ], [ false, [[LEFT]] ]
; CHECK-NEXT: [[L_PHI_MOVED]] = phi i32 [ [[R_PHI_MOVED]], [[RIGHT]] ], [ [[X:%.*]], [[ENTRY]] ], [ [[L_PHI_MOVED]], [[LEFT]] ]
; CHECK-NEXT: [[R_PHI_MOVED]] = phi i32 [ [[R_PHI_MOVED]], [[RIGHT]] ], [ [[Y:%.*]], [[ENTRY]] ], [ [[L]], [[LEFT]] ]
; CHECK-NEXT: br i1 [[GUARD_LEFT]], label [[LEFT]], label [[RIGHT]]
;
entry:
br i1 %PredEntry, label %left, label %right
left:
%L.phi = phi i32 [%X, %entry], [%R.phi, %right]
%L = add i32 %L.phi, 1
br i1 %PredLeft, label %right, label %exit
right:
%R.phi = phi i32 [%Y, %entry], [%L, %left]
br i1 %PredRight, label %left, label %exit
exit:
%Z = phi i32 [%L, %left], [%R.phi, %right]
ret i32 %Z
}
define i32 @feedback_loop(i1 %PredEntry, i1 %PredLeft, i1 %PredRight, i32 %X, i32 %Y) {
; CHECK-LABEL: @feedback_loop(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[IRR_GUARD:%.*]]
; CHECK: left:
; CHECK-NEXT: br i1 [[PREDLEFT:%.*]], label [[IRR_GUARD]], label [[EXIT:%.*]]
; CHECK: right:
; CHECK-NEXT: br i1 [[PREDRIGHT:%.*]], label [[IRR_GUARD]], label [[EXIT]]
; CHECK: exit:
; CHECK-NEXT: [[Z:%.*]] = phi i32 [ [[L_PHI_MOVED:%.*]], [[LEFT:%.*]] ], [ [[R_PHI_MOVED:%.*]], [[RIGHT:%.*]] ]
; CHECK-NEXT: ret i32 [[Z]]
; CHECK: irr.guard:
; CHECK-NEXT: [[GUARD_LEFT:%.*]] = phi i1 [ true, [[RIGHT]] ], [ [[PREDENTRY:%.*]], [[ENTRY:%.*]] ], [ false, [[LEFT]] ]
; CHECK-NEXT: [[L_PHI_MOVED]] = phi i32 [ [[R_PHI_MOVED]], [[RIGHT]] ], [ [[X:%.*]], [[ENTRY]] ], [ [[L_PHI_MOVED]], [[LEFT]] ]
; CHECK-NEXT: [[R_PHI_MOVED]] = phi i32 [ [[R_PHI_MOVED]], [[RIGHT]] ], [ [[Y:%.*]], [[ENTRY]] ], [ [[L_PHI_MOVED]], [[LEFT]] ]
; CHECK-NEXT: br i1 [[GUARD_LEFT]], label [[LEFT]], label [[RIGHT]]
;
entry:
br i1 %PredEntry, label %left, label %right
left:
%L.phi = phi i32 [%X, %entry], [%R.phi, %right]
br i1 %PredLeft, label %right, label %exit
right:
%R.phi = phi i32 [%Y, %entry], [%L.phi, %left]
br i1 %PredRight, label %left, label %exit
exit:
%Z = phi i32 [%L.phi, %left], [%R.phi, %right]
ret i32 %Z
}
define i32 @multiple_predecessors(i1 %PredEntry, i1 %PredA, i1 %PredB, i1 %PredC, i1 %PredD, i32 %X, i32 %Y) {
; CHECK-LABEL: @multiple_predecessors(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[PREDB_INV:%.*]] = xor i1 [[PREDB:%.*]], true
; CHECK-NEXT: br i1 [[PREDENTRY:%.*]], label [[A:%.*]], label [[B:%.*]]
; CHECK: A:
; CHECK-NEXT: [[A_INC:%.*]] = add i32 [[X:%.*]], 1
; CHECK-NEXT: br label [[IRR_GUARD:%.*]]
; CHECK: B:
; CHECK-NEXT: br label [[IRR_GUARD]]
; CHECK: C:
; CHECK-NEXT: br i1 [[PREDC:%.*]], label [[IRR_GUARD]], label [[EXIT:%.*]]
; CHECK: D:
; CHECK-NEXT: [[D_INC:%.*]] = add i32 [[D_PHI_MOVED:%.*]], 1
; CHECK-NEXT: br i1 [[PREDD:%.*]], label [[EXIT]], label [[IRR_GUARD]]
; CHECK: exit:
; CHECK-NEXT: [[RET:%.*]] = phi i32 [ [[C_PHI_MOVED:%.*]], [[C:%.*]] ], [ [[D_INC]], [[D:%.*]] ]
; CHECK-NEXT: ret i32 [[RET]]
; CHECK: irr.guard:
; CHECK-NEXT: [[GUARD_C:%.*]] = phi i1 [ true, [[D]] ], [ [[PREDB_INV]], [[B]] ], [ [[PREDA:%.*]], [[A]] ], [ false, [[C]] ]
; CHECK-NEXT: [[C_PHI_MOVED]] = phi i32 [ [[D_INC]], [[D]] ], [ [[Y:%.*]], [[B]] ], [ [[X]], [[A]] ], [ [[C_PHI_MOVED]], [[C]] ]
; CHECK-NEXT: [[D_PHI_MOVED]] = phi i32 [ [[D_PHI_MOVED]], [[D]] ], [ [[Y]], [[B]] ], [ [[A_INC]], [[A]] ], [ [[C_PHI_MOVED]], [[C]] ]
; CHECK-NEXT: br i1 [[GUARD_C]], label [[C]], label [[D]]
;
entry:
br i1 %PredEntry, label %A, label %B
A:
%A.inc = add i32 %X, 1
br i1 %PredA, label %C, label %D
B:
br i1 %PredB, label %D, label %C
C:
%C.phi = phi i32 [%X, %A], [%Y, %B], [%D.inc, %D]
br i1 %PredC, label %D, label %exit
D:
%D.phi = phi i32 [%A.inc, %A], [%Y, %B], [%C.phi, %C]
%D.inc = add i32 %D.phi, 1
br i1 %PredD, label %exit, label %C
exit:
%ret = phi i32 [%C.phi, %C], [%D.inc, %D]
ret i32 %ret
}
define i32 @separate_predecessors(i1 %PredEntry, i1 %PredA, i1 %PredB, i1 %PredC, i1 %PredD, i32 %X, i32 %Y) {
; CHECK-LABEL: @separate_predecessors(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[PREDENTRY:%.*]], label [[A:%.*]], label [[B:%.*]]
; CHECK: A:
; CHECK-NEXT: [[A_INC:%.*]] = add i32 [[X:%.*]], 1
; CHECK-NEXT: br label [[IRR_GUARD:%.*]]
; CHECK: B:
; CHECK-NEXT: br label [[IRR_GUARD]]
; CHECK: C:
; CHECK-NEXT: br i1 [[PREDC:%.*]], label [[EXIT:%.*]], label [[IRR_GUARD]]
; CHECK: D:
; CHECK-NEXT: [[D_INC:%.*]] = add i32 [[D_PHI_MOVED:%.*]], 1
; CHECK-NEXT: br i1 [[PREDD:%.*]], label [[EXIT]], label [[IRR_GUARD]]
; CHECK: exit:
; CHECK-NEXT: [[RET:%.*]] = phi i32 [ [[C_PHI_MOVED:%.*]], [[C:%.*]] ], [ [[D_INC]], [[D:%.*]] ]
; CHECK-NEXT: ret i32 [[RET]]
; CHECK: irr.guard:
; CHECK-NEXT: [[GUARD_C:%.*]] = phi i1 [ true, [[D]] ], [ true, [[A]] ], [ false, [[C]] ], [ false, [[B]] ]
; CHECK-NEXT: [[C_PHI_MOVED]] = phi i32 [ [[D_INC]], [[D]] ], [ [[X]], [[A]] ], [ [[C_PHI_MOVED]], [[C]] ], [ undef, [[B]] ]
; CHECK-NEXT: [[D_PHI_MOVED]] = phi i32 [ [[D_PHI_MOVED]], [[D]] ], [ undef, [[A]] ], [ [[C_PHI_MOVED]], [[C]] ], [ [[Y:%.*]], [[B]] ]
; CHECK-NEXT: br i1 [[GUARD_C]], label [[C]], label [[D]]
;
entry:
br i1 %PredEntry, label %A, label %B
A:
%A.inc = add i32 %X, 1
br label %C
B:
br label %D
C:
%C.phi = phi i32 [%X, %A], [%D.inc, %D]
br i1 %PredC, label %exit, label %D
D:
%D.phi = phi i32 [%Y, %B], [%C.phi, %C]
%D.inc = add i32 %D.phi, 1
br i1 %PredD, label %exit, label %C
exit:
%ret = phi i32 [%C.phi, %C], [%D.inc, %D]
ret i32 %ret
}
define void @four_headers(i1 %PredEntry, i1 %PredX, i1 %PredY, i1 %PredD) {
; CHECK-LABEL: @four_headers(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[PREDENTRY:%.*]], label [[X:%.*]], label [[Y:%.*]]
; CHECK: X:
; CHECK-NEXT: br label [[IRR_GUARD:%.*]]
; CHECK: Y:
; CHECK-NEXT: br label [[IRR_GUARD]]
; CHECK: A:
; CHECK-NEXT: br label [[IRR_GUARD]]
; CHECK: B:
; CHECK-NEXT: br label [[IRR_GUARD]]
; CHECK: C:
; CHECK-NEXT: br label [[IRR_GUARD]]
; CHECK: D:
; CHECK-NEXT: br i1 [[PREDD:%.*]], label [[EXIT:%.*]], label [[IRR_GUARD]]
; CHECK: exit:
; CHECK-NEXT: ret void
; CHECK: irr.guard:
; CHECK-NEXT: [[GUARD_A:%.*]] = phi i1 [ true, [[D:%.*]] ], [ [[PREDX:%.*]], [[X]] ], [ false, [[A:%.*]] ], [ false, [[B:%.*]] ], [ false, [[Y]] ], [ false, [[C:%.*]] ]
; CHECK-NEXT: [[GUARD_B:%.*]] = phi i1 [ false, [[D]] ], [ true, [[X]] ], [ true, [[A]] ], [ false, [[B]] ], [ false, [[Y]] ], [ false, [[C]] ]
; CHECK-NEXT: [[GUARD_C:%.*]] = phi i1 [ false, [[D]] ], [ false, [[X]] ], [ false, [[A]] ], [ true, [[B]] ], [ [[PREDY:%.*]], [[Y]] ], [ false, [[C]] ]
; CHECK-NEXT: br i1 [[GUARD_A]], label [[A]], label [[IRR_GUARD1:%.*]]
; CHECK: irr.guard1:
; CHECK-NEXT: br i1 [[GUARD_B]], label [[B]], label [[IRR_GUARD2:%.*]]
; CHECK: irr.guard2:
; CHECK-NEXT: br i1 [[GUARD_C]], label [[C]], label [[D]]
;
entry:
br i1 %PredEntry, label %X, label %Y
X:
br i1 %PredX, label %A, label %B
Y:
br i1 %PredY, label %C, label %D
A:
br label %B
B:
br label %C
C:
br label %D
D:
br i1 %PredD, label %exit, label %A
exit:
ret void
}
define i32 @hidden_nodes(i1 %PredEntry, i1 %PredA, i1 %PredB, i1 %PredC, i1 %PredD, i32 %X, i32 %Y) {
; CHECK-LABEL: @hidden_nodes(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[IRR_GUARD:%.*]]
; CHECK: A:
; CHECK-NEXT: [[A_INC:%.*]] = add i32 [[A_PHI_MOVED:%.*]], 1
; CHECK-NEXT: br label [[IRR_GUARD]]
; CHECK: B:
; CHECK-NEXT: br label [[C:%.*]]
; CHECK: C:
; CHECK-NEXT: [[C_INC:%.*]] = add i32 [[B_PHI_MOVED:%.*]], 1
; CHECK-NEXT: br label [[D:%.*]]
; CHECK: D:
; CHECK-NEXT: br i1 [[PREDD:%.*]], label [[EXIT:%.*]], label [[E:%.*]]
; CHECK: E:
; CHECK-NEXT: br label [[IRR_GUARD]]
; CHECK: exit:
; CHECK-NEXT: ret i32 [[B_PHI_MOVED]]
; CHECK: irr.guard:
; CHECK-NEXT: [[GUARD_A:%.*]] = phi i1 [ true, [[E]] ], [ [[PREDENTRY:%.*]], [[ENTRY:%.*]] ], [ false, [[A:%.*]] ]
; CHECK-NEXT: [[A_PHI_MOVED]] = phi i32 [ [[C_INC]], [[E]] ], [ [[X:%.*]], [[ENTRY]] ], [ [[A_PHI_MOVED]], [[A]] ]
; CHECK-NEXT: [[B_PHI_MOVED]] = phi i32 [ undef, [[E]] ], [ [[Y:%.*]], [[ENTRY]] ], [ [[A_INC]], [[A]] ]
; CHECK-NEXT: br i1 [[GUARD_A]], label [[A]], label [[B:%.*]]
;
entry:
br i1 %PredEntry, label %A, label %B
A:
%A.phi = phi i32 [%X, %entry], [%C.inc, %E]
%A.inc = add i32 %A.phi, 1
br label %B
B:
%B.phi = phi i32 [%A.inc, %A], [%Y, %entry]
br label %C
C:
%C.inc = add i32 %B.phi, 1
br label %D
D:
br i1 %PredD, label %exit, label %E
E:
br label %A
exit:
ret i32 %B.phi
}