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llvm-project/llvm/test/Transforms/SimplifyCFG/jump-threading-live-on-exit.ll
LU-JOHN a757f23404
[SimplifyCFG] Extend jump-threading to allow live local defs (#135079) 
Extend jump-threading to allow local defs that are live outside of the
threaded block. Allow threading to destinations where the local defs are
not live.

---------

Signed-off-by: John Lu <John.Lu@amd.com>
2025-07-31 09:44:14 -04:00

196 lines
6.2 KiB
LLVM
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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt -passes=simplifycfg -S < %s | FileCheck %s
; Allow jump-threading when values defined in the block are live outside of the block
; to those destinations in which the values are dead.
define void @testA(ptr %ptrA, ptr %ptrB, i64 %a, i64 %b) {
; CHECK-LABEL: define void @testA(
; CHECK-SAME: ptr [[PTRA:%.*]], ptr [[PTRB:%.*]], i64 [[A:%.*]], i64 [[B:%.*]]) {
; CHECK-NEXT: [[MAINA:.*:]]
; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[A]], [[B]]
; CHECK-NEXT: br i1 [[COND]], label %[[IFA:.*]], label %[[MAINC:.*]]
; CHECK: [[IFA]]:
; CHECK-NEXT: [[TMP0:%.*]] = load i64, ptr [[PTRA]], align 4
; CHECK-NEXT: store i64 [[TMP0]], ptr [[PTRB]], align 4
; CHECK-NEXT: br label %[[MAINC]]
; CHECK: [[MAINC]]:
; CHECK-NEXT: ret void
;
mainA:
%cond = icmp slt i64 %a, %b
br i1 %cond, label %ifA, label %mainB
ifA:
%518 = load i64, ptr %ptrA
br label %mainB
; %value is live outside of block mainB, but jump-threading
; can still occur to destination mainC, since %value is dead there.
; Subsequent CFG simplifications will create one if block.
mainB:
%value = phi i64 [ %518, %ifA ], [ zeroinitializer, %mainA ]
br i1 %cond, label %ifB, label %mainC
ifB:
store i64 %value, ptr %ptrB
br label %mainC
mainC:
ret void
}
define void @testB(ptr %ptrA, ptr %ptrB, i64 %a, i64 %b, i64 %c) {
; CHECK-LABEL: define void @testB(
; CHECK-SAME: ptr [[PTRA:%.*]], ptr [[PTRB:%.*]], i64 [[A:%.*]], i64 [[B:%.*]], i64 [[C:%.*]]) {
; CHECK-NEXT: [[MAINA:.*:]]
; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[A]], [[B]]
; CHECK-NEXT: br i1 [[COND]], label %[[IFA:.*]], label %[[MAINC:.*]]
; CHECK: [[IFA]]:
; CHECK-NEXT: [[TMP0:%.*]] = load i64, ptr [[PTRA]], align 4
; CHECK-NEXT: [[COND2:%.*]] = icmp slt i64 [[A]], [[C]]
; CHECK-NEXT: [[PTR_ARM1:%.*]] = getelementptr i64, ptr [[PTRB]], i64 8
; CHECK-NEXT: [[PTR_ARM2:%.*]] = getelementptr i64, ptr [[PTRB]], i64 16
; CHECK-NEXT: [[PTRC:%.*]] = select i1 [[COND2]], ptr [[PTR_ARM1]], ptr [[PTR_ARM2]]
; CHECK-NEXT: store i64 [[TMP0]], ptr [[PTRC]], align 4
; CHECK-NEXT: br label %[[MAINC]]
; CHECK: [[MAINC]]:
; CHECK-NEXT: ret void
;
mainA:
%cond = icmp slt i64 %a, %b
br i1 %cond, label %ifA, label %mainB
ifA:
%518 = load i64, ptr %ptrA
br label %mainB
; Use of %value is not in either immediate destination of mainB.
mainB:
%value = phi i64 [ %518, %ifA ], [ zeroinitializer, %mainA ]
br i1 %cond, label %ifB, label %mainC
ifB:
%cond2 = icmp slt i64 %a, %c
br i1 %cond2, label %ifB_arm1, label %ifB_arm2
ifB_arm1:
%ptr_arm1 = getelementptr i64, ptr %ptrB, i64 8
br label %ifB_join
ifB_arm2:
%ptr_arm2 = getelementptr i64, ptr %ptrB, i64 16
br label %ifB_join
ifB_join:
%ptrC = phi ptr [ %ptr_arm1, %ifB_arm1 ], [ %ptr_arm2, %ifB_arm2 ]
store i64 %value, ptr %ptrC
br label %mainC
mainC:
ret void
}
; Jump-threading is not done since %value is live in both destinations.
define void @testA_negative(ptr %ptrA, ptr %ptrB, ptr %ptrD, i64 %a, i64 %b) {
; CHECK-LABEL: define void @testA_negative(
; CHECK-SAME: ptr [[PTRA:%.*]], ptr [[PTRB:%.*]], ptr [[PTRD:%.*]], i64 [[A:%.*]], i64 [[B:%.*]]) {
; CHECK-NEXT: [[MAINA:.*]]:
; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[A]], [[B]]
; CHECK-NEXT: br i1 [[COND]], label %[[IFA:.*]], label %[[MAINB:.*]]
; CHECK: [[IFA]]:
; CHECK-NEXT: [[TMP0:%.*]] = load i64, ptr [[PTRA]], align 4
; CHECK-NEXT: br label %[[MAINB]]
; CHECK: [[MAINB]]:
; CHECK-NEXT: [[VALUE:%.*]] = phi i64 [ [[TMP0]], %[[IFA]] ], [ 0, %[[MAINA]] ]
; CHECK-NEXT: br i1 [[COND]], label %[[IFB:.*]], label %[[MAINC:.*]]
; CHECK: [[IFB]]:
; CHECK-NEXT: store i64 [[VALUE]], ptr [[PTRB]], align 4
; CHECK-NEXT: br label %[[MAINC]]
; CHECK: [[MAINC]]:
; CHECK-NEXT: store i64 [[VALUE]], ptr [[PTRD]], align 4
; CHECK-NEXT: ret void
;
mainA:
%cond = icmp slt i64 %a, %b
br i1 %cond, label %ifA, label %mainB
ifA:
%518 = load i64, ptr %ptrA
br label %mainB
mainB:
%value = phi i64 [ %518, %ifA ], [ zeroinitializer, %mainA ]
br i1 %cond, label %ifB, label %mainC
ifB:
store i64 %value, ptr %ptrB
br label %mainC
mainC:
store i64 %value, ptr %ptrD
ret void
}
; Jump-threading is not done since %value is live in both destinations.
define void @testB_negative(ptr %ptrA, ptr %ptrB, ptr %ptrD, i64 %a, i64 %b, i64 %c) {
; CHECK-LABEL: define void @testB_negative(
; CHECK-SAME: ptr [[PTRA:%.*]], ptr [[PTRB:%.*]], ptr [[PTRD:%.*]], i64 [[A:%.*]], i64 [[B:%.*]], i64 [[C:%.*]]) {
; CHECK-NEXT: [[MAINA:.*]]:
; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[A]], [[B]]
; CHECK-NEXT: br i1 [[COND]], label %[[IFA:.*]], label %[[MAINB:.*]]
; CHECK: [[IFA]]:
; CHECK-NEXT: [[TMP0:%.*]] = load i64, ptr [[PTRA]], align 4
; CHECK-NEXT: br label %[[MAINB]]
; CHECK: [[MAINB]]:
; CHECK-NEXT: [[VALUE:%.*]] = phi i64 [ [[TMP0]], %[[IFA]] ], [ 0, %[[MAINA]] ]
; CHECK-NEXT: br i1 [[COND]], label %[[IFB:.*]], label %[[MAINC:.*]]
; CHECK: [[IFB]]:
; CHECK-NEXT: [[COND2:%.*]] = icmp slt i64 [[A]], [[C]]
; CHECK-NEXT: [[PTR_ARM1:%.*]] = getelementptr i64, ptr [[PTRB]], i64 8
; CHECK-NEXT: [[PTR_ARM2:%.*]] = getelementptr i64, ptr [[PTRB]], i64 16
; CHECK-NEXT: [[PTRC:%.*]] = select i1 [[COND2]], ptr [[PTR_ARM1]], ptr [[PTR_ARM2]]
; CHECK-NEXT: store i64 [[VALUE]], ptr [[PTRC]], align 4
; CHECK-NEXT: br label %[[MAINC]]
; CHECK: [[MAINC]]:
; CHECK-NEXT: store i64 [[VALUE]], ptr [[PTRD]], align 4
; CHECK-NEXT: ret void
;
mainA:
%cond = icmp slt i64 %a, %b
br i1 %cond, label %ifA, label %mainB
ifA:
%518 = load i64, ptr %ptrA
br label %mainB
mainB:
%value = phi i64 [ %518, %ifA ], [ zeroinitializer, %mainA ]
br i1 %cond, label %ifB, label %mainC
ifB:
%cond2 = icmp slt i64 %a, %c
br i1 %cond2, label %ifB_arm1, label %ifB_arm2
ifB_arm1:
%ptr_arm1 = getelementptr i64, ptr %ptrB, i64 8
br label %ifB_join
ifB_arm2:
%ptr_arm2 = getelementptr i64, ptr %ptrB, i64 16
br label %ifB_join
ifB_join:
%ptrC = phi ptr [ %ptr_arm1, %ifB_arm1 ], [ %ptr_arm2, %ifB_arm2 ]
store i64 %value, ptr %ptrC
br label %mainC
mainC:
store i64 %value, ptr %ptrD
ret void
}
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