xref: /llvm-project/llvm/test/Transforms/SimplifyCFG/avoid-complex-phi.ll (revision e4688b98cd2b86035a2b563a8db0819710d6275a)

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt < %s -max-phi-entries-increase-after-removing-empty-block=12 -passes=simplifycfg -S | FileCheck --check-prefixes=CHECK-12 %s
; RUN: opt < %s -max-phi-entries-increase-after-removing-empty-block=11 -passes=simplifycfg -S | FileCheck --check-prefixes=CHECK-11 %s
; RUN: opt < %s -max-phi-entries-increase-after-removing-empty-block=4 -passes=simplifycfg -S | FileCheck --check-prefixes=CHECK-4 %s
;
; This test has the following CFG:
;   1. entry has a switch to 4 blocks: B1 - B4
;   2. For B1 and B2, it branches to B5 and B6
;   3. For B3 and B4, it branches to B5 and B7
;   4. In B5, %val is defined as phi taking values from B1 to B4
;   5. B5, B6, B7 branch to block Merge unconditionally
;   6. Block Merge has 5 phis(%x1 - %x4 and %val_merge).
;
; If we remove B5, %x1 - %x4 will increase the number of phi entries by (4 - 1) * 4 = 12. For %val_merge, since the value taking from B5
; is defined in B5, it will not increase the number of phi entries (it can be considered as move the entries from %val to
; %val_merge). Therefore, removing B5 will increase the number of phi entries by 12 (not (4 - 1) * 5 = 15).
;
; If we remove B6 / B7, it will increase the number of phi entries by (2 - 1) * 5 = 5.
;
; In the first test, max-phi-entries-increase-after-removing-empty-block is set to be 12, then B5 will be removed.
; In the second test, max-phi-entries-increase-after-removing-empty-block is set to be 11, then B5 should not be removed,
; but B6 and B7 can be removed.
; In the third test, max-phi-entries-increase-after-removing-empty-block is set to be 4, then no BB can be removed.
;
define void @foo(i32 %a, i32 %val1, i32 %val2, i32 %val3, i32 %val4) {
; CHECK-12-LABEL: define void @foo(
; CHECK-12-SAME: i32 [[A:%.*]], i32 [[VAL1:%.*]], i32 [[VAL2:%.*]], i32 [[VAL3:%.*]], i32 [[VAL4:%.*]]) {
; CHECK-12-NEXT:  [[ENTRY:.*:]]
; CHECK-12-NEXT:    switch i32 [[A]], label %[[B1:.*]] [
; CHECK-12-NEXT:      i32 4, label %[[B4:.*]]
; CHECK-12-NEXT:      i32 2, label %[[B2:.*]]
; CHECK-12-NEXT:      i32 3, label %[[B3:.*]]
; CHECK-12-NEXT:    ]
; CHECK-12:       [[B1]]:
; CHECK-12-NEXT:    [[CMP1:%.*]] = icmp eq i32 [[VAL1]], 1
; CHECK-12-NEXT:    br i1 [[CMP1]], label %[[B6:.*]], label %[[MERGE:.*]]
; CHECK-12:       [[B2]]:
; CHECK-12-NEXT:    [[CMP2:%.*]] = icmp eq i32 [[VAL2]], 2
; CHECK-12-NEXT:    br i1 [[CMP2]], label %[[B6]], label %[[MERGE]]
; CHECK-12:       [[B3]]:
; CHECK-12-NEXT:    [[CMP3:%.*]] = icmp eq i32 [[VAL3]], 3
; CHECK-12-NEXT:    br i1 [[CMP3]], label %[[B7:.*]], label %[[MERGE]]
; CHECK-12:       [[B4]]:
; CHECK-12-NEXT:    [[CMP4:%.*]] = icmp eq i32 [[VAL4]], 4
; CHECK-12-NEXT:    br i1 [[CMP4]], label %[[B7]], label %[[MERGE]]
; CHECK-12:       [[B6]]:
; CHECK-12-NEXT:    br label %[[MERGE]]
; CHECK-12:       [[B7]]:
; CHECK-12-NEXT:    br label %[[MERGE]]
; CHECK-12:       [[MERGE]]:
; CHECK-12-NEXT:    [[X1:%.*]] = phi i16 [ 0, %[[B6]] ], [ 2, %[[B7]] ], [ 1, %[[B4]] ], [ 1, %[[B3]] ], [ 1, %[[B2]] ], [ 1, %[[B1]] ]
; CHECK-12-NEXT:    [[X2:%.*]] = phi i16 [ 0, %[[B6]] ], [ 2, %[[B7]] ], [ 2, %[[B4]] ], [ 2, %[[B3]] ], [ 2, %[[B2]] ], [ 2, %[[B1]] ]
; CHECK-12-NEXT:    [[X3:%.*]] = phi i16 [ 0, %[[B6]] ], [ 2, %[[B7]] ], [ 3, %[[B4]] ], [ 3, %[[B3]] ], [ 3, %[[B2]] ], [ 3, %[[B1]] ]
; CHECK-12-NEXT:    [[X4:%.*]] = phi i16 [ 0, %[[B6]] ], [ 2, %[[B7]] ], [ 4, %[[B4]] ], [ 4, %[[B3]] ], [ 4, %[[B2]] ], [ 4, %[[B1]] ]
; CHECK-12-NEXT:    [[VAL_MERGE:%.*]] = phi i32 [ 0, %[[B6]] ], [ 2, %[[B7]] ], [ [[VAL1]], %[[B1]] ], [ [[VAL2]], %[[B2]] ], [ [[VAL3]], %[[B3]] ], [ [[VAL4]], %[[B4]] ]
; CHECK-12-NEXT:    ret void
;
; CHECK-11-LABEL: define void @foo(
; CHECK-11-SAME: i32 [[A:%.*]], i32 [[VAL1:%.*]], i32 [[VAL2:%.*]], i32 [[VAL3:%.*]], i32 [[VAL4:%.*]]) {
; CHECK-11-NEXT:  [[ENTRY:.*:]]
; CHECK-11-NEXT:    switch i32 [[A]], label %[[B1:.*]] [
; CHECK-11-NEXT:      i32 4, label %[[B4:.*]]
; CHECK-11-NEXT:      i32 2, label %[[B2:.*]]
; CHECK-11-NEXT:      i32 3, label %[[B3:.*]]
; CHECK-11-NEXT:    ]
; CHECK-11:       [[B1]]:
; CHECK-11-NEXT:    [[CMP1:%.*]] = icmp eq i32 [[VAL1]], 1
; CHECK-11-NEXT:    br i1 [[CMP1]], label %[[MERGE:.*]], label %[[B5:.*]]
; CHECK-11:       [[B2]]:
; CHECK-11-NEXT:    [[CMP2:%.*]] = icmp eq i32 [[VAL2]], 2
; CHECK-11-NEXT:    br i1 [[CMP2]], label %[[MERGE]], label %[[B5]]
; CHECK-11:       [[B3]]:
; CHECK-11-NEXT:    [[CMP3:%.*]] = icmp eq i32 [[VAL3]], 3
; CHECK-11-NEXT:    br i1 [[CMP3]], label %[[MERGE]], label %[[B5]]
; CHECK-11:       [[B4]]:
; CHECK-11-NEXT:    [[CMP4:%.*]] = icmp eq i32 [[VAL4]], 4
; CHECK-11-NEXT:    br i1 [[CMP4]], label %[[MERGE]], label %[[B5]]
; CHECK-11:       [[B5]]:
; CHECK-11-NEXT:    [[VAL:%.*]] = phi i32 [ [[VAL1]], %[[B1]] ], [ [[VAL2]], %[[B2]] ], [ [[VAL3]], %[[B3]] ], [ [[VAL4]], %[[B4]] ]
; CHECK-11-NEXT:    br label %[[MERGE]]
; CHECK-11:       [[MERGE]]:
; CHECK-11-NEXT:    [[X1:%.*]] = phi i16 [ 1, %[[B5]] ], [ 0, %[[B2]] ], [ 0, %[[B1]] ], [ 2, %[[B4]] ], [ 2, %[[B3]] ]
; CHECK-11-NEXT:    [[X2:%.*]] = phi i16 [ 2, %[[B5]] ], [ 0, %[[B2]] ], [ 0, %[[B1]] ], [ 2, %[[B4]] ], [ 2, %[[B3]] ]
; CHECK-11-NEXT:    [[X3:%.*]] = phi i16 [ 3, %[[B5]] ], [ 0, %[[B2]] ], [ 0, %[[B1]] ], [ 2, %[[B4]] ], [ 2, %[[B3]] ]
; CHECK-11-NEXT:    [[X4:%.*]] = phi i16 [ 4, %[[B5]] ], [ 0, %[[B2]] ], [ 0, %[[B1]] ], [ 2, %[[B4]] ], [ 2, %[[B3]] ]
; CHECK-11-NEXT:    [[VAL_MERGE:%.*]] = phi i32 [ [[VAL]], %[[B5]] ], [ 0, %[[B2]] ], [ 0, %[[B1]] ], [ 2, %[[B4]] ], [ 2, %[[B3]] ]
; CHECK-11-NEXT:    ret void
;
; CHECK-4-LABEL: define void @foo(
; CHECK-4-SAME: i32 [[A:%.*]], i32 [[VAL1:%.*]], i32 [[VAL2:%.*]], i32 [[VAL3:%.*]], i32 [[VAL4:%.*]]) {
; CHECK-4-NEXT:  [[ENTRY:.*:]]
; CHECK-4-NEXT:    switch i32 [[A]], label %[[B1:.*]] [
; CHECK-4-NEXT:      i32 4, label %[[B4:.*]]
; CHECK-4-NEXT:      i32 2, label %[[B2:.*]]
; CHECK-4-NEXT:      i32 3, label %[[B3:.*]]
; CHECK-4-NEXT:    ]
; CHECK-4:       [[B1]]:
; CHECK-4-NEXT:    [[CMP1:%.*]] = icmp eq i32 [[VAL1]], 1
; CHECK-4-NEXT:    br i1 [[CMP1]], label %[[B6:.*]], label %[[B5:.*]]
; CHECK-4:       [[B2]]:
; CHECK-4-NEXT:    [[CMP2:%.*]] = icmp eq i32 [[VAL2]], 2
; CHECK-4-NEXT:    br i1 [[CMP2]], label %[[B6]], label %[[B5]]
; CHECK-4:       [[B3]]:
; CHECK-4-NEXT:    [[CMP3:%.*]] = icmp eq i32 [[VAL3]], 3
; CHECK-4-NEXT:    br i1 [[CMP3]], label %[[B7:.*]], label %[[B5]]
; CHECK-4:       [[B4]]:
; CHECK-4-NEXT:    [[CMP4:%.*]] = icmp eq i32 [[VAL4]], 4
; CHECK-4-NEXT:    br i1 [[CMP4]], label %[[B7]], label %[[B5]]
; CHECK-4:       [[B5]]:
; CHECK-4-NEXT:    [[VAL:%.*]] = phi i32 [ [[VAL1]], %[[B1]] ], [ [[VAL2]], %[[B2]] ], [ [[VAL3]], %[[B3]] ], [ [[VAL4]], %[[B4]] ]
; CHECK-4-NEXT:    br label %[[MERGE:.*]]
; CHECK-4:       [[B6]]:
; CHECK-4-NEXT:    br label %[[MERGE]]
; CHECK-4:       [[B7]]:
; CHECK-4-NEXT:    br label %[[MERGE]]
; CHECK-4:       [[MERGE]]:
; CHECK-4-NEXT:    [[X1:%.*]] = phi i16 [ 1, %[[B5]] ], [ 0, %[[B6]] ], [ 2, %[[B7]] ]
; CHECK-4-NEXT:    [[X2:%.*]] = phi i16 [ 2, %[[B5]] ], [ 0, %[[B6]] ], [ 2, %[[B7]] ]
; CHECK-4-NEXT:    [[X3:%.*]] = phi i16 [ 3, %[[B5]] ], [ 0, %[[B6]] ], [ 2, %[[B7]] ]
; CHECK-4-NEXT:    [[X4:%.*]] = phi i16 [ 4, %[[B5]] ], [ 0, %[[B6]] ], [ 2, %[[B7]] ]
; CHECK-4-NEXT:    [[VAL_MERGE:%.*]] = phi i32 [ [[VAL]], %[[B5]] ], [ 0, %[[B6]] ], [ 2, %[[B7]] ]
; CHECK-4-NEXT:    ret void
;
entry:
  switch i32 %a, label %B1 [
  i32 4, label %B4
  i32 2, label %B2
  i32 3, label %B3
  ]

B1:                                               ; preds = %entry
  %cmp1 = icmp eq i32 %val1, 1
  br i1 %cmp1, label %B6, label %B5

B2:                                               ; preds = %entry
  %cmp2 = icmp eq i32 %val2, 2
  br i1 %cmp2, label %B6, label %B5

B3:                                               ; preds = %entry
  %cmp3 = icmp eq i32 %val3, 3
  br i1 %cmp3, label %B7, label %B5

B4:                                               ; preds = %entry
  %cmp4 = icmp eq i32 %val4, 4
  br i1 %cmp4, label %B7, label %B5

B5:                                              ; preds = %B4, %B3, %B2, %B1
  %val = phi i32 [ %val1, %B1 ], [ %val2, %B2 ], [ %val3, %B3 ], [ %val4, %B4 ]
  br label %Merge

B6:                                              ; preds = %B2, %B1
  br label %Merge

B7:                                              ; preds = %B4, %B3
  br label %Merge

Merge:                                            ; preds = %B7, %B6, %B5
  %x1 = phi i16 [ 1, %B5 ], [ 0, %B6 ], [ 2, %B7 ]
  %x2 = phi i16 [ 2, %B5 ], [ 0, %B6 ], [ 2, %B7 ]
  %x3 = phi i16 [ 3, %B5 ], [ 0, %B6 ], [ 2, %B7 ]
  %x4 = phi i16 [ 4, %B5 ], [ 0, %B6 ], [ 2, %B7 ]
  %val_merge = phi i32 [ %val, %B5 ], [ 0, %B6 ], [ 2, %B7 ]
  ret void
}