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clang-p2996/llvm/test/Transforms/InstCombine/phi-select-constant.ll
Nikita Popov 3bc38fb27a [InstCombine] Generalize and consolidate phi translation check (#106051) 
The foldOpIntoPhi() transforms requires all operands to be
phi-translatable. This can be the case either because they are phi nodes
in the same block, or because the operand dominates the block.

Currently, most callers of foldOpIntoPhi() satisfy this pre-condition by
requiring a constant operand, which trivially dominates everything. Only
selects had handling for variable operands.

Move this logic into foldOpIntoPhi(), so things are handled correctly if
other callers are generalized. Also make the implementation a bit more
general by querying the dominator tree.
2024-09-04 16:22:43 +02:00

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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -S -passes=instcombine | FileCheck %s
@A = extern_weak global i32, align 4
@B = extern_weak global i32, align 4
define i32 @foo(i1 %which) {
; CHECK-LABEL: @foo(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[WHICH:%.*]], label [[FINAL:%.*]], label [[DELAY:%.*]]
; CHECK: delay:
; CHECK-NEXT: [[CMP:%.*]] = icmp eq ptr @A, @B
; CHECK-NEXT: [[TMP0:%.*]] = select i1 [[CMP]], i32 2, i32 1
; CHECK-NEXT: br label [[FINAL]]
; CHECK: final:
; CHECK-NEXT: [[USE2:%.*]] = phi i32 [ 1, [[ENTRY:%.*]] ], [ [[TMP0]], [[DELAY]] ]
; CHECK-NEXT: ret i32 [[USE2]]
;
entry:
br i1 %which, label %final, label %delay
delay:
%cmp = icmp eq ptr @A, @B
br label %final
final:
%use2 = phi i1 [ false, %entry ], [ %cmp, %delay ]
%value = select i1 %use2, i32 2, i32 1
ret i32 %value
}
; test folding of select into phi for vectors.
define <4 x i64> @vec1(i1 %which) {
; CHECK-LABEL: @vec1(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[WHICH:%.*]], label [[FINAL:%.*]], label [[DELAY:%.*]]
; CHECK: delay:
; CHECK-NEXT: br label [[FINAL]]
; CHECK: final:
; CHECK-NEXT: [[PHINODE:%.*]] = phi <4 x i64> [ zeroinitializer, [[ENTRY:%.*]] ], [ <i64 0, i64 0, i64 126, i64 127>, [[DELAY]] ]
; CHECK-NEXT: ret <4 x i64> [[PHINODE]]
;
entry:
br i1 %which, label %final, label %delay
delay:
br label %final
final:
%phinode = phi <4 x i1> [ <i1 true, i1 true, i1 true, i1 true>, %entry ], [ <i1 true, i1 true, i1 false, i1 false>, %delay ]
%sel = select <4 x i1> %phinode, <4 x i64> zeroinitializer, <4 x i64> <i64 124, i64 125, i64 126, i64 127>
ret <4 x i64> %sel
}
define <4 x i64> @vec2(i1 %which) {
; CHECK-LABEL: @vec2(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[WHICH:%.*]], label [[FINAL:%.*]], label [[DELAY:%.*]]
; CHECK: delay:
; CHECK-NEXT: br label [[FINAL]]
; CHECK: final:
; CHECK-NEXT: [[PHINODE:%.*]] = phi <4 x i64> [ <i64 124, i64 125, i64 126, i64 127>, [[ENTRY:%.*]] ], [ <i64 0, i64 125, i64 0, i64 127>, [[DELAY]] ]
; CHECK-NEXT: ret <4 x i64> [[PHINODE]]
;
entry:
br i1 %which, label %final, label %delay
delay:
br label %final
final:
%phinode = phi <4 x i1> [ <i1 false, i1 false, i1 false, i1 false>, %entry ], [ <i1 true, i1 false, i1 true, i1 false>, %delay ]
%sel = select <4 x i1> %phinode, <4 x i64> zeroinitializer, <4 x i64> <i64 124, i64 125, i64 126, i64 127>
ret <4 x i64> %sel
}
; Test PR33364
; Insert the generated select into the same block as the incoming phi value.
; phi has constant vectors along with a single non-constant vector as operands.
define <2 x i8> @vec3(i1 %cond1, i1 %cond2, <2 x i1> %x, <2 x i8> %y, <2 x i8> %z) {
; CHECK-LABEL: @vec3(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[COND1:%.*]], label [[IF1:%.*]], label [[ELSE:%.*]]
; CHECK: if1:
; CHECK-NEXT: br i1 [[COND2:%.*]], label [[IF2:%.*]], label [[ELSE]]
; CHECK: if2:
; CHECK-NEXT: br label [[ELSE]]
; CHECK: else:
; CHECK-NEXT: [[PHI:%.*]] = phi <2 x i1> [ [[X:%.*]], [[IF2]] ], [ <i1 false, i1 true>, [[ENTRY:%.*]] ], [ <i1 true, i1 false>, [[IF1]] ]
; CHECK-NEXT: [[SEL:%.*]] = select <2 x i1> [[PHI]], <2 x i8> [[Y:%.*]], <2 x i8> [[Z:%.*]]
; CHECK-NEXT: ret <2 x i8> [[SEL]]
;
entry:
br i1 %cond1, label %if1, label %else
if1:
br i1 %cond2, label %if2, label %else
if2:
br label %else
else:
%phi = phi <2 x i1> [ %x, %if2 ], [ <i1 0, i1 1>, %entry ], [ <i1 1, i1 0>, %if1 ]
%sel = select <2 x i1> %phi, <2 x i8> %y, <2 x i8> %z
ret <2 x i8> %sel
}
; Don't crash on unreachable IR.
define void @PR48369(i32 %a, ptr %p) {
; CHECK-LABEL: @PR48369(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[PHI_CMP:%.*]] = icmp sgt i32 [[A:%.*]], 0
; CHECK-NEXT: br label [[BB1:%.*]]
; CHECK: bb1:
; CHECK-NEXT: [[CMP:%.*]] = phi i1 [ [[PHI_CMP]], [[DEADBB:%.*]] ], [ true, [[ENTRY:%.*]] ]
; CHECK-NEXT: [[SHL:%.*]] = select i1 [[CMP]], i32 256, i32 0
; CHECK-NEXT: store i32 [[SHL]], ptr [[P:%.*]], align 4
; CHECK-NEXT: br label [[END:%.*]]
; CHECK: deadbb:
; CHECK-NEXT: br label [[BB1]]
; CHECK: end:
; CHECK-NEXT: ret void
;
entry:
%phi.cmp = icmp sgt i32 %a, 0
br label %bb1
bb1:
%cmp = phi i1 [ %phi.cmp, %deadbb ], [ true, %entry ]
%shl = select i1 %cmp, i32 256, i32 0
store i32 %shl, ptr %p
br label %end
deadbb:
br label %bb1
end:
ret void
}
define i16 @sink_to_unreachable_crash(i1 %a) {
; CHECK-LABEL: @sink_to_unreachable_crash(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[INF_LOOP:%.*]]
; CHECK: inf_loop:
; CHECK-NEXT: br label [[INF_LOOP]]
; CHECK: unreachable:
; CHECK-NEXT: ret i16 poison
;
entry:
%s = select i1 %a, i16 0, i16 5
br label %inf_loop
inf_loop:
br label %inf_loop
unreachable: ; No predecessors!
ret i16 %s
}
define i32 @phi_trans(i1 %c, i1 %c2, i32 %v) {
; CHECK-LABEL: @phi_trans(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[C:%.*]], label [[IF:%.*]], label [[ELSE:%.*]]
; CHECK: if:
; CHECK-NEXT: [[V2:%.*]] = add i32 [[V:%.*]], 1
; CHECK-NEXT: br label [[JOIN:%.*]]
; CHECK: else:
; CHECK-NEXT: [[V3:%.*]] = mul i32 [[V]], 3
; CHECK-NEXT: [[V5:%.*]] = lshr i32 [[V]], 1
; CHECK-NEXT: [[TMP0:%.*]] = select i1 [[C2:%.*]], i32 [[V3]], i32 [[V5]]
; CHECK-NEXT: br label [[JOIN]]
; CHECK: join:
; CHECK-NEXT: [[PHI1:%.*]] = phi i32 [ [[V2]], [[IF]] ], [ [[TMP0]], [[ELSE]] ]
; CHECK-NEXT: ret i32 [[PHI1]]
;
entry:
br i1 %c, label %if, label %else
if:
%v2 = add i32 %v, 1
%v4 = shl i32 %v, 1
br label %join
else:
%v3 = mul i32 %v, 3
%v5 = lshr i32 %v, 1
br label %join
join:
%phi1 = phi i1 [ true, %if ], [ %c2, %else ]
%phi2 = phi i32 [ %v2, %if ], [ %v3, %else ]
%phi3 = phi i32 [ %v4, %if ], [ %v5, %else ]
%sel = select i1 %phi1, i32 %phi2, i32 %phi3
ret i32 %sel
}
define i32 @dominating_values_select_same_block(i1 %c1, i1 %c2, ptr %p, ptr %p2) {
; CHECK-LABEL: @dominating_values_select_same_block(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[B:%.*]] = load i32, ptr [[P2:%.*]], align 4
; CHECK-NEXT: br i1 [[C1:%.*]], label [[FINAL:%.*]], label [[DELAY:%.*]]
; CHECK: delay:
; CHECK-NEXT: [[A:%.*]] = load i32, ptr [[P:%.*]], align 4
; CHECK-NEXT: [[TMP0:%.*]] = select i1 [[C2:%.*]], i32 [[A]], i32 [[B]]
; CHECK-NEXT: br label [[FINAL]]
; CHECK: final:
; CHECK-NEXT: [[USE2:%.*]] = phi i32 [ [[B]], [[ENTRY:%.*]] ], [ [[TMP0]], [[DELAY]] ]
; CHECK-NEXT: ret i32 [[USE2]]
;
entry:
%a = load i32, ptr %p
%b = load i32, ptr %p2
br i1 %c1, label %final, label %delay
delay:
br label %final
final:
%use2 = phi i1 [ false, %entry ], [ %c2, %delay ]
%value = select i1 %use2, i32 %a, i32 %b
ret i32 %value
}
define i32 @dominating_values_select_not_same_block(i1 %c1, i1 %c2, ptr %p, ptr %p2) {
; CHECK-LABEL: @dominating_values_select_not_same_block(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[B:%.*]] = load i32, ptr [[P2:%.*]], align 4
; CHECK-NEXT: br i1 [[C1:%.*]], label [[FINAL:%.*]], label [[DELAY:%.*]]
; CHECK: delay:
; CHECK-NEXT: [[A:%.*]] = load i32, ptr [[P:%.*]], align 4
; CHECK-NEXT: [[TMP0:%.*]] = select i1 [[C2:%.*]], i32 [[A]], i32 [[B]]
; CHECK-NEXT: br label [[FINAL]]
; CHECK: final:
; CHECK-NEXT: [[USE2:%.*]] = phi i32 [ [[B]], [[ENTRY:%.*]] ], [ [[TMP0]], [[DELAY]] ]
; CHECK-NEXT: br label [[SPLIT:%.*]]
; CHECK: split:
; CHECK-NEXT: ret i32 [[USE2]]
;
entry:
%a = load i32, ptr %p
%b = load i32, ptr %p2
br i1 %c1, label %final, label %delay
delay:
br label %final
final:
%use2 = phi i1 [ false, %entry ], [ %c2, %delay ]
br label %split
split:
%value = select i1 %use2, i32 %a, i32 %b
ret i32 %value
}
define i32 @not_dominating_values(i1 %c1, i1 %c2, ptr %p, ptr %p2) {
; CHECK-LABEL: @not_dominating_values(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[A:%.*]] = load i32, ptr [[P:%.*]], align 4
; CHECK-NEXT: br i1 [[C1:%.*]], label [[FINAL:%.*]], label [[DELAY:%.*]]
; CHECK: delay:
; CHECK-NEXT: br label [[FINAL]]
; CHECK: final:
; CHECK-NEXT: [[USE2:%.*]] = phi i1 [ false, [[ENTRY:%.*]] ], [ [[C2:%.*]], [[DELAY]] ]
; CHECK-NEXT: [[B:%.*]] = load i32, ptr [[P2:%.*]], align 4
; CHECK-NEXT: [[VALUE:%.*]] = select i1 [[USE2]], i32 [[A]], i32 [[B]]
; CHECK-NEXT: ret i32 [[VALUE]]
;
entry:
%a = load i32, ptr %p
br i1 %c1, label %final, label %delay
delay:
br label %final
final:
%use2 = phi i1 [ false, %entry ], [ %c2, %delay ]
%b = load i32, ptr %p2
%value = select i1 %use2, i32 %a, i32 %b
ret i32 %value
}
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