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llvm/llvm-project/3c9812eeea4d857d26c32e156a58897b2ec2ad85^!/.
commit
3c9812eeea4d857d26c32e156a58897b2ec2ad85
[log]
author
Florian Hahn <flo@fhahn.com>
Fri May 23 15:46:34 2025 +0100
committer
Florian Hahn <flo@fhahn.com>
Fri May 23 15:46:34 2025 +0100
tree
7676a0a8d68be9f0861bf61ffe588872eb9d9ee2
parent
723984126327e1dc0e76ac24720a6f7a9e0ec388 [diff]
[LoopPeel] Add tests for peeling last iteration with multiple exits.

diff --git a/llvm/test/Transforms/LoopUnroll/peel-last-iteration-multi-exit.ll b/llvm/test/Transforms/LoopUnroll/peel-last-iteration-multi-exit.ll
new file mode 100644
index 0000000..89accea
--- /dev/null
+++ b/llvm/test/Transforms/LoopUnroll/peel-last-iteration-multi-exit.ll

@@ -0,0 +1,315 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -p loop-unroll -unroll-full-max-count=0 -S %s | FileCheck %s
+
+declare void @foo(i32)
+declare i1 @cond()
+
+define i64 @loop_with_3_exits(i64 %n) {
+; CHECK-LABEL: define i64 @loop_with_3_exits(
+; CHECK-SAME: i64 [[N:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    br label %[[LOOP_HEADER:.*]]
+; CHECK:       [[LOOP_HEADER]]:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT:    br i1 false, label %[[LOOP_LATCH]], label %[[THEN:.*]]
+; CHECK:       [[THEN]]:
+; CHECK-NEXT:    [[C:%.*]] = icmp eq i64 [[IV]], [[N]]
+; CHECK-NEXT:    br i1 [[C]], label %[[EXIT_0:.*]], label %[[THEN_2:.*]]
+; CHECK:       [[THEN_2]]:
+; CHECK-NEXT:    call void @foo(i32 0)
+; CHECK-NEXT:    br label %[[LOOP_LATCH]]
+; CHECK:       [[LOOP_LATCH]]:
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[EC:%.*]] = icmp eq i64 [[IV]], 63
+; CHECK-NEXT:    br i1 [[EC]], label %[[EXIT_1:.*]], label %[[LOOP_HEADER]]
+; CHECK:       [[EXIT_0]]:
+; CHECK-NEXT:    [[IV_LCSSA:%.*]] = phi i64 [ [[IV]], %[[THEN]] ]
+; CHECK-NEXT:    ret i64 [[IV_LCSSA]]
+; CHECK:       [[EXIT_1]]:
+; CHECK-NEXT:    [[IV_NEXT_LCSSA:%.*]] = phi i64 [ [[IV_NEXT]], %[[LOOP_LATCH]] ]
+; CHECK-NEXT:    ret i64 [[IV_NEXT_LCSSA]]
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  br i1 false, label %loop.latch, label %then
+
+then:
+  %c = icmp eq i64 %iv, %n
+  br i1 %c, label %exit.0, label %then.2
+
+then.2:
+  call void @foo(i32 0)
+  br label %loop.latch
+
+loop.latch:
+  %iv.next = add i64 %iv, 1
+  %ec = icmp eq i64 %iv, 63
+  br i1 %ec, label %exit.1, label %loop.header
+
+exit.0:
+  ret i64 %iv
+
+exit.1:
+  ret i64 %iv.next
+}
+
+define void @peel_last_multi_exit_btc_computable_no_exit_values(i32 %n) {
+; CHECK-LABEL: define void @peel_last_multi_exit_btc_computable_no_exit_values(
+; CHECK-SAME: i32 [[N:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    br label %[[LOOP_HEADER:.*]]
+; CHECK:       [[LOOP_HEADER]]:
+; CHECK-NEXT:    [[IV_NEXT_LCSSA:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[IV_NEXT_PEEL:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT:    [[EC_0_PEEL:%.*]] = icmp eq i32 [[IV_NEXT_LCSSA]], [[N]]
+; CHECK-NEXT:    br i1 [[EC_0_PEEL]], label %[[EXIT:.*]], label %[[LOOP_LATCH]]
+; CHECK:       [[LOOP_LATCH]]:
+; CHECK-NEXT:    [[C_PEEL:%.*]] = icmp eq i32 [[IV_NEXT_LCSSA]], 16
+; CHECK-NEXT:    [[COND_PEEL:%.*]] = select i1 [[C_PEEL]], i32 10, i32 20
+; CHECK-NEXT:    call void @foo(i32 [[COND_PEEL]])
+; CHECK-NEXT:    [[IV_NEXT_PEEL]] = add i32 [[IV_NEXT_LCSSA]], 1
+; CHECK-NEXT:    [[EC_PEEL:%.*]] = icmp eq i32 [[IV_NEXT_PEEL]], 17
+; CHECK-NEXT:    br i1 [[EC_PEEL]], label %[[EXIT]], label %[[LOOP_HEADER]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %ec.0 = icmp eq i32 %iv, %n
+  br i1 %ec.0, label %exit, label %loop.latch
+
+loop.latch:
+  %c = icmp eq i32 %iv, 16
+  %cond = select i1 %c, i32 10, i32 20
+  call void @foo(i32 %cond)
+  %iv.next = add i32 %iv, 1
+  %ec = icmp eq i32 %iv.next, 17
+  br i1 %ec, label %exit, label %loop.header
+
+exit:
+  ret void
+}
+
+define i32 @peel_last_multi_exit_btc_computable_exit_constant_values(i32 %n) {
+; CHECK-LABEL: define i32 @peel_last_multi_exit_btc_computable_exit_constant_values(
+; CHECK-SAME: i32 [[N:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    br label %[[LOOP_HEADER:.*]]
+; CHECK:       [[LOOP_HEADER]]:
+; CHECK-NEXT:    [[IV_NEXT_LCSSA:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[IV_NEXT_PEEL:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT:    [[EC_0_PEEL:%.*]] = icmp eq i32 [[IV_NEXT_LCSSA]], [[N]]
+; CHECK-NEXT:    br i1 [[EC_0_PEEL]], label %[[EXIT:.*]], label %[[LOOP_LATCH]]
+; CHECK:       [[LOOP_LATCH]]:
+; CHECK-NEXT:    [[C_PEEL:%.*]] = icmp eq i32 [[IV_NEXT_LCSSA]], 16
+; CHECK-NEXT:    [[COND_PEEL:%.*]] = select i1 [[C_PEEL]], i32 10, i32 20
+; CHECK-NEXT:    call void @foo(i32 [[COND_PEEL]])
+; CHECK-NEXT:    [[IV_NEXT_PEEL]] = add i32 [[IV_NEXT_LCSSA]], 1
+; CHECK-NEXT:    [[EC_PEEL:%.*]] = icmp eq i32 [[IV_NEXT_PEEL]], 17
+; CHECK-NEXT:    br i1 [[EC_PEEL]], label %[[EXIT]], label %[[LOOP_HEADER]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 1, %[[LOOP_HEADER]] ], [ 2, %[[LOOP_LATCH]] ]
+; CHECK-NEXT:    ret i32 [[RES]]
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %ec.0 = icmp eq i32 %iv, %n
+  br i1 %ec.0, label %exit, label %loop.latch
+
+loop.latch:
+  %c = icmp eq i32 %iv, 16
+  %cond = select i1 %c, i32 10, i32 20
+  call void @foo(i32 %cond)
+  %iv.next = add i32 %iv, 1
+  %ec = icmp eq i32 %iv.next, 17
+  br i1 %ec, label %exit, label %loop.header
+
+exit:
+  %res = phi i32 [ 1, %loop.header ], [ 2, %loop.latch ]
+  ret i32 %res
+}
+
+define i32 @peel_last_multi_exit_btc_computable_exit_values_from_loop(i32 %n) {
+; CHECK-LABEL: define i32 @peel_last_multi_exit_btc_computable_exit_values_from_loop(
+; CHECK-SAME: i32 [[N:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    br label %[[LOOP_HEADER:.*]]
+; CHECK:       [[LOOP_HEADER]]:
+; CHECK-NEXT:    [[IV_NEXT_LCSSA:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[IV_NEXT_PEEL:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT:    [[EC_0_PEEL:%.*]] = icmp eq i32 [[IV_NEXT_LCSSA]], [[N]]
+; CHECK-NEXT:    br i1 [[EC_0_PEEL]], label %[[EXIT:.*]], label %[[LOOP_LATCH]]
+; CHECK:       [[LOOP_LATCH]]:
+; CHECK-NEXT:    [[C_PEEL:%.*]] = icmp eq i32 [[IV_NEXT_LCSSA]], 16
+; CHECK-NEXT:    [[COND_PEEL:%.*]] = select i1 [[C_PEEL]], i32 10, i32 20
+; CHECK-NEXT:    call void @foo(i32 [[COND_PEEL]])
+; CHECK-NEXT:    [[IV_NEXT_PEEL]] = add i32 [[IV_NEXT_LCSSA]], 1
+; CHECK-NEXT:    [[EC_PEEL:%.*]] = icmp eq i32 [[IV_NEXT_PEEL]], 17
+; CHECK-NEXT:    br i1 [[EC_PEEL]], label %[[EXIT]], label %[[LOOP_HEADER]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ [[IV_NEXT_LCSSA]], %[[LOOP_HEADER]] ], [ [[COND_PEEL]], %[[LOOP_LATCH]] ]
+; CHECK-NEXT:    ret i32 [[RES]]
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %ec.0 = icmp eq i32 %iv, %n
+  br i1 %ec.0, label %exit, label %loop.latch
+
+loop.latch:
+  %c = icmp eq i32 %iv, 16
+  %cond = select i1 %c, i32 10, i32 20
+  call void @foo(i32 %cond)
+  %iv.next = add i32 %iv, 1
+  %ec = icmp eq i32 %iv.next, 17
+  br i1 %ec, label %exit, label %loop.header
+
+exit:
+  %res = phi i32 [ %iv, %loop.header ], [ %cond, %loop.latch ]
+  ret i32 %res
+}
+
+define i32 @peel_last_multi_exit_btc_computable_exit_values_from_loop_multiple_exit_blocks(i32 %n) {
+; CHECK-LABEL: define i32 @peel_last_multi_exit_btc_computable_exit_values_from_loop_multiple_exit_blocks(
+; CHECK-SAME: i32 [[N:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    br label %[[LOOP_HEADER:.*]]
+; CHECK:       [[LOOP_HEADER]]:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT:    [[EC_0:%.*]] = icmp eq i32 [[IV]], [[N]]
+; CHECK-NEXT:    br i1 [[EC_0]], label %[[EXIT_0:.*]], label %[[LOOP_LATCH]]
+; CHECK:       [[LOOP_LATCH]]:
+; CHECK-NEXT:    [[C:%.*]] = icmp eq i32 [[IV]], 16
+; CHECK-NEXT:    [[COND:%.*]] = select i1 [[C]], i32 10, i32 20
+; CHECK-NEXT:    call void @foo(i32 [[COND]])
+; CHECK-NEXT:    [[IV_NEXT]] = add i32 [[IV]], 1
+; CHECK-NEXT:    [[EC:%.*]] = icmp eq i32 [[IV_NEXT]], 17
+; CHECK-NEXT:    br i1 [[EC]], label %[[EXIT_1:.*]], label %[[LOOP_HEADER]]
+; CHECK:       [[EXIT_0]]:
+; CHECK-NEXT:    [[RES_0:%.*]] = phi i32 [ [[IV]], %[[LOOP_HEADER]] ]
+; CHECK-NEXT:    ret i32 [[RES_0]]
+; CHECK:       [[EXIT_1]]:
+; CHECK-NEXT:    [[RES_1:%.*]] = phi i32 [ [[COND]], %[[LOOP_LATCH]] ]
+; CHECK-NEXT:    ret i32 [[RES_1]]
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %ec.0 = icmp eq i32 %iv, %n
+  br i1 %ec.0, label %exit.0, label %loop.latch
+
+loop.latch:
+  %c = icmp eq i32 %iv, 16
+  %cond = select i1 %c, i32 10, i32 20
+  call void @foo(i32 %cond)
+  %iv.next = add i32 %iv, 1
+  %ec = icmp eq i32 %iv.next, 17
+  br i1 %ec, label %exit.1, label %loop.header
+
+exit.0:
+  %res.0 = phi i32 [ %iv, %loop.header ]
+  ret i32 %res.0
+
+exit.1:
+  %res.1 = phi i32 [ %cond, %loop.latch ]
+  ret i32 %res.1
+}
+
+define i64 @peel_last_btc_not_computable() {
+; CHECK-LABEL: define i64 @peel_last_btc_not_computable() {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    br label %[[LOOP_HEADER:.*]]
+; CHECK:       [[LOOP_HEADER]]:
+; CHECK-NEXT:    [[IV_NEXT_LCSSA:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[IV_NEXT_PEEL:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT:    [[EC_0_PEEL:%.*]] = call i1 @cond()
+; CHECK-NEXT:    br i1 [[EC_0_PEEL]], label %[[THEN_1:.*]], label %[[EXIT:.*]]
+; CHECK:       [[THEN_1]]:
+; CHECK-NEXT:    call void @foo(i32 1)
+; CHECK-NEXT:    [[C_PEEL:%.*]] = icmp eq i64 [[IV_NEXT_LCSSA]], 7
+; CHECK-NEXT:    br i1 [[C_PEEL]], label %[[LOOP_LATCH]], label %[[THEN_2:.*]]
+; CHECK:       [[THEN_2]]:
+; CHECK-NEXT:    call void @foo(i32 2)
+; CHECK-NEXT:    br label %[[LOOP_LATCH]]
+; CHECK:       [[LOOP_LATCH]]:
+; CHECK-NEXT:    [[IV_NEXT_PEEL]] = add i64 [[IV_NEXT_LCSSA]], 1
+; CHECK-NEXT:    [[EXITCOND_PEEL:%.*]] = icmp ne i64 [[IV_NEXT_PEEL]], 8
+; CHECK-NEXT:    br i1 [[EXITCOND_PEEL]], label %[[LOOP_HEADER]], label %[[EXIT]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    [[RES:%.*]] = phi i64 [ 1, %[[LOOP_LATCH]] ], [ 2, %[[LOOP_HEADER]] ]
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %ec.0 = call i1 @cond()
+  br i1 %ec.0, label %then.1, label %exit
+
+then.1:
+  call void @foo(i32 1)
+  %c = icmp eq i64 %iv, 7
+  br i1 %c, label %loop.latch, label %then.2
+
+then.2:
+  call void @foo(i32 2)
+  br label %loop.latch
+
+loop.latch:
+  %iv.next = add i64 %iv, 1
+  %exitcond = icmp ne i64 %iv.next, 8
+  br i1 %exitcond, label %loop.header, label %exit
+
+exit:
+  %res = phi i64 [ 1, %loop.latch ], [ 2, %loop.header ]
+  ret i64 %res
+}
+
+define void @peel_exit_count_larger_than_btc(i32 %n) {
+; CHECK-LABEL: define void @peel_exit_count_larger_than_btc(
+; CHECK-SAME: i32 [[N:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    br label %[[LOOP_HEADER:.*]]
+; CHECK:       [[LOOP_HEADER]]:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
+; CHECK-NEXT:    [[EC_0:%.*]] = icmp eq i32 [[IV]], 10
+; CHECK-NEXT:    br i1 [[EC_0]], label %[[EXIT:.*]], label %[[LOOP_LATCH]]
+; CHECK:       [[LOOP_LATCH]]:
+; CHECK-NEXT:    [[C:%.*]] = icmp eq i32 [[IV]], 9
+; CHECK-NEXT:    [[COND:%.*]] = select i1 [[C]], i32 10, i32 20
+; CHECK-NEXT:    call void @foo(i32 [[COND]])
+; CHECK-NEXT:    [[IV_NEXT]] = add i32 [[IV]], 1
+; CHECK-NEXT:    [[EC:%.*]] = icmp eq i32 [[IV_NEXT]], 17
+; CHECK-NEXT:    br i1 [[EC]], label %[[EXIT]], label %[[LOOP_HEADER]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %ec.0 = icmp eq i32 %iv, 10
+  br i1 %ec.0, label %exit, label %loop.latch
+
+loop.latch:
+  %c = icmp eq i32 %iv, 9
+  %cond = select i1 %c, i32 10, i32 20
+  call void @foo(i32 %cond)
+  %iv.next = add i32 %iv, 1
+  %ec = icmp eq i32 %iv.next, 17
+  br i1 %ec, label %exit, label %loop.header
+
+exit:
+  ret void
+}