[llvm] [InlineCost] Consider the default branch when calculating cost (PR #77856)

Quentin Dian via llvm-commits llvm-commits at lists.llvm.org
Tue Feb 6 16:40:56 PST 2024


https://github.com/DianQK updated https://github.com/llvm/llvm-project/pull/77856

>From 479121181b8800047e053aa815921cb309f0171d Mon Sep 17 00:00:00 2001
From: DianQK <dianqk at dianqk.net>
Date: Wed, 10 Jan 2024 22:47:58 +0800
Subject: [PATCH 1/6] Pre-commit test cases

---
 .../Inline/inline-switch-default-2.ll         | 334 ++++++++++++++++++
 .../Inline/inline-switch-default.ll           | 250 +++++++++++++
 2 files changed, 584 insertions(+)
 create mode 100644 llvm/test/Transforms/Inline/inline-switch-default-2.ll
 create mode 100644 llvm/test/Transforms/Inline/inline-switch-default.ll

diff --git a/llvm/test/Transforms/Inline/inline-switch-default-2.ll b/llvm/test/Transforms/Inline/inline-switch-default-2.ll
new file mode 100644
index 0000000000000..dd889124e3b5b
--- /dev/null
+++ b/llvm/test/Transforms/Inline/inline-switch-default-2.ll
@@ -0,0 +1,334 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt %s -S -passes=inline -inline-threshold=21 | FileCheck %s
+
+; Check for scenarios without TTI.
+
+define i64 @foo1(i64 %0) {
+; LOOKUPTABLE-LABEL: define i64 @foo1(
+; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
+; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH_I:%.*]] [
+; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
+; LOOKUPTABLE-NEXT:    ]
+; LOOKUPTABLE:       branch_0.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT:%.*]]
+; LOOKUPTABLE:       branch_2.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
+; LOOKUPTABLE:       branch_4.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
+; LOOKUPTABLE:       branch_6.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
+; LOOKUPTABLE:       default_branch.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
+; LOOKUPTABLE:       bar1.exit:
+; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ], [ 3, [[DEFAULT_BRANCH_I]] ]
+; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+;
+; SWITCH-LABEL: define i64 @foo1(
+; SWITCH-SAME: i64 [[TMP0:%.*]]) {
+; SWITCH-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH_I:%.*]] [
+; SWITCH-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
+; SWITCH-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
+; SWITCH-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
+; SWITCH-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
+; SWITCH-NEXT:    ]
+; SWITCH:       branch_0.i:
+; SWITCH-NEXT:    br label [[BAR1_EXIT:%.*]]
+; SWITCH:       branch_2.i:
+; SWITCH-NEXT:    br label [[BAR1_EXIT]]
+; SWITCH:       branch_4.i:
+; SWITCH-NEXT:    br label [[BAR1_EXIT]]
+; SWITCH:       branch_6.i:
+; SWITCH-NEXT:    br label [[BAR1_EXIT]]
+; SWITCH:       default_branch.i:
+; SWITCH-NEXT:    br label [[BAR1_EXIT]]
+; SWITCH:       bar1.exit:
+; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ], [ 3, [[DEFAULT_BRANCH_I]] ]
+; SWITCH-NEXT:    ret i64 [[TMP2]]
+;
+; CHECK-LABEL: define i64 @foo1(
+; CHECK-SAME: i64 [[TMP0:%.*]]) {
+; CHECK-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH_I:%.*]] [
+; CHECK-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
+; CHECK-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
+; CHECK-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
+; CHECK-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       branch_0.i:
+; CHECK-NEXT:    br label [[BAR1_EXIT:%.*]]
+; CHECK:       branch_2.i:
+; CHECK-NEXT:    br label [[BAR1_EXIT]]
+; CHECK:       branch_4.i:
+; CHECK-NEXT:    br label [[BAR1_EXIT]]
+; CHECK:       branch_6.i:
+; CHECK-NEXT:    br label [[BAR1_EXIT]]
+; CHECK:       default_branch.i:
+; CHECK-NEXT:    br label [[BAR1_EXIT]]
+; CHECK:       bar1.exit:
+; CHECK-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ], [ 3, [[DEFAULT_BRANCH_I]] ]
+; CHECK-NEXT:    ret i64 [[TMP2]]
+;
+  %2 = call i64 @bar1(i64 %0)
+  ret i64 %2
+}
+
+define i64 @foo2(i64 %0) {
+; LOOKUPTABLE-LABEL: define i64 @foo2(
+; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
+; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT_I:%.*]] [
+; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
+; LOOKUPTABLE-NEXT:    ]
+; LOOKUPTABLE:       branch_0.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR2_EXIT:%.*]]
+; LOOKUPTABLE:       branch_2.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR2_EXIT]]
+; LOOKUPTABLE:       branch_4.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR2_EXIT]]
+; LOOKUPTABLE:       branch_6.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR2_EXIT]]
+; LOOKUPTABLE:       unreachabledefault.i:
+; LOOKUPTABLE-NEXT:    unreachable
+; LOOKUPTABLE:       bar2.exit:
+; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ]
+; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+;
+; SWITCH-LABEL: define i64 @foo2(
+; SWITCH-SAME: i64 [[TMP0:%.*]]) {
+; SWITCH-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT_I:%.*]] [
+; SWITCH-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
+; SWITCH-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
+; SWITCH-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
+; SWITCH-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
+; SWITCH-NEXT:    ]
+; SWITCH:       branch_0.i:
+; SWITCH-NEXT:    br label [[BAR2_EXIT:%.*]]
+; SWITCH:       branch_2.i:
+; SWITCH-NEXT:    br label [[BAR2_EXIT]]
+; SWITCH:       branch_4.i:
+; SWITCH-NEXT:    br label [[BAR2_EXIT]]
+; SWITCH:       branch_6.i:
+; SWITCH-NEXT:    br label [[BAR2_EXIT]]
+; SWITCH:       unreachabledefault.i:
+; SWITCH-NEXT:    unreachable
+; SWITCH:       bar2.exit:
+; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ]
+; SWITCH-NEXT:    ret i64 [[TMP2]]
+;
+; CHECK-LABEL: define i64 @foo2(
+; CHECK-SAME: i64 [[TMP0:%.*]]) {
+; CHECK-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT_I:%.*]] [
+; CHECK-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
+; CHECK-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
+; CHECK-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
+; CHECK-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       branch_0.i:
+; CHECK-NEXT:    br label [[BAR2_EXIT:%.*]]
+; CHECK:       branch_2.i:
+; CHECK-NEXT:    br label [[BAR2_EXIT]]
+; CHECK:       branch_4.i:
+; CHECK-NEXT:    br label [[BAR2_EXIT]]
+; CHECK:       branch_6.i:
+; CHECK-NEXT:    br label [[BAR2_EXIT]]
+; CHECK:       unreachabledefault.i:
+; CHECK-NEXT:    unreachable
+; CHECK:       bar2.exit:
+; CHECK-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ]
+; CHECK-NEXT:    ret i64 [[TMP2]]
+;
+  %2 = call i64 @bar2(i64 %0)
+  ret i64 %2
+}
+
+define i64 @bar1(i64 %0) {
+; LOOKUPTABLE-LABEL: define i64 @bar1(
+; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
+; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH:%.*]] [
+; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0:%.*]]
+; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2:%.*]]
+; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4:%.*]]
+; LOOKUPTABLE-NEXT:      i64 6, label [[BRANCH_6:%.*]]
+; LOOKUPTABLE-NEXT:    ]
+; LOOKUPTABLE:       branch_0:
+; LOOKUPTABLE-NEXT:    br label [[EXIT:%.*]]
+; LOOKUPTABLE:       branch_2:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       branch_4:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       branch_6:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       default_branch:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       exit:
+; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ], [ 3, [[DEFAULT_BRANCH]] ]
+; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+;
+; SWITCH-LABEL: define i64 @bar1(
+; SWITCH-SAME: i64 [[TMP0:%.*]]) {
+; SWITCH-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH:%.*]] [
+; SWITCH-NEXT:      i64 0, label [[BRANCH_0:%.*]]
+; SWITCH-NEXT:      i64 2, label [[BRANCH_2:%.*]]
+; SWITCH-NEXT:      i64 4, label [[BRANCH_4:%.*]]
+; SWITCH-NEXT:      i64 6, label [[BRANCH_6:%.*]]
+; SWITCH-NEXT:    ]
+; SWITCH:       branch_0:
+; SWITCH-NEXT:    br label [[EXIT:%.*]]
+; SWITCH:       branch_2:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       branch_4:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       branch_6:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       default_branch:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       exit:
+; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ], [ 3, [[DEFAULT_BRANCH]] ]
+; SWITCH-NEXT:    ret i64 [[TMP2]]
+;
+; CHECK-LABEL: define i64 @bar1(
+; CHECK-SAME: i64 [[TMP0:%.*]]) {
+; CHECK-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH:%.*]] [
+; CHECK-NEXT:      i64 0, label [[BRANCH_0:%.*]]
+; CHECK-NEXT:      i64 2, label [[BRANCH_2:%.*]]
+; CHECK-NEXT:      i64 4, label [[BRANCH_4:%.*]]
+; CHECK-NEXT:      i64 6, label [[BRANCH_6:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       branch_0:
+; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK:       branch_2:
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       branch_4:
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       branch_6:
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       default_branch:
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ], [ 3, [[DEFAULT_BRANCH]] ]
+; CHECK-NEXT:    ret i64 [[TMP2]]
+;
+  switch i64 %0, label %default_branch [
+  i64 0, label %branch_0
+  i64 2, label %branch_2
+  i64 4, label %branch_4
+  i64 6, label %branch_6
+  ]
+
+branch_0:
+  br label %exit
+
+branch_2:
+  br label %exit
+
+branch_4:
+  br label %exit
+
+branch_6:
+  br label %exit
+
+default_branch:
+  br label %exit
+
+exit:
+  %2 = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ], [ 3, %default_branch ]
+  ret i64 %2
+}
+
+define i64 @bar2(i64 %0) {
+; LOOKUPTABLE-LABEL: define i64 @bar2(
+; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
+; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT:%.*]] [
+; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0:%.*]]
+; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2:%.*]]
+; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4:%.*]]
+; LOOKUPTABLE-NEXT:      i64 6, label [[BRANCH_6:%.*]]
+; LOOKUPTABLE-NEXT:    ]
+; LOOKUPTABLE:       branch_0:
+; LOOKUPTABLE-NEXT:    br label [[EXIT:%.*]]
+; LOOKUPTABLE:       branch_2:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       branch_4:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       branch_6:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       unreachabledefault:
+; LOOKUPTABLE-NEXT:    unreachable
+; LOOKUPTABLE:       exit:
+; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ]
+; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+;
+; SWITCH-LABEL: define i64 @bar2(
+; SWITCH-SAME: i64 [[TMP0:%.*]]) {
+; SWITCH-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT:%.*]] [
+; SWITCH-NEXT:      i64 0, label [[BRANCH_0:%.*]]
+; SWITCH-NEXT:      i64 2, label [[BRANCH_2:%.*]]
+; SWITCH-NEXT:      i64 4, label [[BRANCH_4:%.*]]
+; SWITCH-NEXT:      i64 6, label [[BRANCH_6:%.*]]
+; SWITCH-NEXT:    ]
+; SWITCH:       branch_0:
+; SWITCH-NEXT:    br label [[EXIT:%.*]]
+; SWITCH:       branch_2:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       branch_4:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       branch_6:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       unreachabledefault:
+; SWITCH-NEXT:    unreachable
+; SWITCH:       exit:
+; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ]
+; SWITCH-NEXT:    ret i64 [[TMP2]]
+;
+; CHECK-LABEL: define i64 @bar2(
+; CHECK-SAME: i64 [[TMP0:%.*]]) {
+; CHECK-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT:%.*]] [
+; CHECK-NEXT:      i64 0, label [[BRANCH_0:%.*]]
+; CHECK-NEXT:      i64 2, label [[BRANCH_2:%.*]]
+; CHECK-NEXT:      i64 4, label [[BRANCH_4:%.*]]
+; CHECK-NEXT:      i64 6, label [[BRANCH_6:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       branch_0:
+; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK:       branch_2:
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       branch_4:
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       branch_6:
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       unreachabledefault:
+; CHECK-NEXT:    unreachable
+; CHECK:       exit:
+; CHECK-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ]
+; CHECK-NEXT:    ret i64 [[TMP2]]
+;
+  switch i64 %0, label %unreachabledefault [
+  i64 0, label %branch_0
+  i64 2, label %branch_2
+  i64 4, label %branch_4
+  i64 6, label %branch_6
+  ]
+
+branch_0:
+  br label %exit
+
+branch_2:
+  br label %exit
+
+branch_4:
+  br label %exit
+
+branch_6:
+  br label %exit
+
+unreachabledefault:
+  unreachable
+
+exit:
+  %2 = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ]
+  ret i64 %2
+}
diff --git a/llvm/test/Transforms/Inline/inline-switch-default.ll b/llvm/test/Transforms/Inline/inline-switch-default.ll
new file mode 100644
index 0000000000000..da95b9f5a458e
--- /dev/null
+++ b/llvm/test/Transforms/Inline/inline-switch-default.ll
@@ -0,0 +1,250 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt %s -S -passes=inline -inline-threshold=26 -min-jump-table-entries=4 | FileCheck %s -check-prefix=LOOKUPTABLE
+; RUN: opt %s -S -passes=inline -inline-threshold=21 -min-jump-table-entries=5 | FileCheck %s -check-prefix=SWITCH
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; FIXME: The `bar1` should not be inlined.
+
+define i64 @foo1(i64 %0) {
+; LOOKUPTABLE-LABEL: define i64 @foo1(
+; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
+; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH_I:%.*]] [
+; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
+; LOOKUPTABLE-NEXT:    ]
+; LOOKUPTABLE:       branch_0.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT:%.*]]
+; LOOKUPTABLE:       branch_2.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
+; LOOKUPTABLE:       branch_4.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
+; LOOKUPTABLE:       branch_6.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
+; LOOKUPTABLE:       default_branch.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
+; LOOKUPTABLE:       bar1.exit:
+; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ], [ 3, [[DEFAULT_BRANCH_I]] ]
+; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+;
+; SWITCH-LABEL: define i64 @foo1(
+; SWITCH-SAME: i64 [[TMP0:%.*]]) {
+; SWITCH-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH_I:%.*]] [
+; SWITCH-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
+; SWITCH-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
+; SWITCH-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
+; SWITCH-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
+; SWITCH-NEXT:    ]
+; SWITCH:       branch_0.i:
+; SWITCH-NEXT:    br label [[BAR1_EXIT:%.*]]
+; SWITCH:       branch_2.i:
+; SWITCH-NEXT:    br label [[BAR1_EXIT]]
+; SWITCH:       branch_4.i:
+; SWITCH-NEXT:    br label [[BAR1_EXIT]]
+; SWITCH:       branch_6.i:
+; SWITCH-NEXT:    br label [[BAR1_EXIT]]
+; SWITCH:       default_branch.i:
+; SWITCH-NEXT:    br label [[BAR1_EXIT]]
+; SWITCH:       bar1.exit:
+; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ], [ 3, [[DEFAULT_BRANCH_I]] ]
+; SWITCH-NEXT:    ret i64 [[TMP2]]
+;
+  %2 = call i64 @bar1(i64 %0)
+  ret i64 %2
+}
+
+define i64 @foo2(i64 %0) {
+; LOOKUPTABLE-LABEL: define i64 @foo2(
+; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
+; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT_I:%.*]] [
+; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
+; LOOKUPTABLE-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
+; LOOKUPTABLE-NEXT:    ]
+; LOOKUPTABLE:       branch_0.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR2_EXIT:%.*]]
+; LOOKUPTABLE:       branch_2.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR2_EXIT]]
+; LOOKUPTABLE:       branch_4.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR2_EXIT]]
+; LOOKUPTABLE:       branch_6.i:
+; LOOKUPTABLE-NEXT:    br label [[BAR2_EXIT]]
+; LOOKUPTABLE:       unreachabledefault.i:
+; LOOKUPTABLE-NEXT:    unreachable
+; LOOKUPTABLE:       bar2.exit:
+; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ]
+; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+;
+; SWITCH-LABEL: define i64 @foo2(
+; SWITCH-SAME: i64 [[TMP0:%.*]]) {
+; SWITCH-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT_I:%.*]] [
+; SWITCH-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
+; SWITCH-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
+; SWITCH-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
+; SWITCH-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
+; SWITCH-NEXT:    ]
+; SWITCH:       branch_0.i:
+; SWITCH-NEXT:    br label [[BAR2_EXIT:%.*]]
+; SWITCH:       branch_2.i:
+; SWITCH-NEXT:    br label [[BAR2_EXIT]]
+; SWITCH:       branch_4.i:
+; SWITCH-NEXT:    br label [[BAR2_EXIT]]
+; SWITCH:       branch_6.i:
+; SWITCH-NEXT:    br label [[BAR2_EXIT]]
+; SWITCH:       unreachabledefault.i:
+; SWITCH-NEXT:    unreachable
+; SWITCH:       bar2.exit:
+; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ]
+; SWITCH-NEXT:    ret i64 [[TMP2]]
+;
+  %2 = call i64 @bar2(i64 %0)
+  ret i64 %2
+}
+
+define i64 @bar1(i64 %0) {
+; LOOKUPTABLE-LABEL: define i64 @bar1(
+; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
+; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH:%.*]] [
+; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0:%.*]]
+; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2:%.*]]
+; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4:%.*]]
+; LOOKUPTABLE-NEXT:      i64 6, label [[BRANCH_6:%.*]]
+; LOOKUPTABLE-NEXT:    ]
+; LOOKUPTABLE:       branch_0:
+; LOOKUPTABLE-NEXT:    br label [[EXIT:%.*]]
+; LOOKUPTABLE:       branch_2:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       branch_4:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       branch_6:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       default_branch:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       exit:
+; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ], [ 3, [[DEFAULT_BRANCH]] ]
+; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+;
+; SWITCH-LABEL: define i64 @bar1(
+; SWITCH-SAME: i64 [[TMP0:%.*]]) {
+; SWITCH-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH:%.*]] [
+; SWITCH-NEXT:      i64 0, label [[BRANCH_0:%.*]]
+; SWITCH-NEXT:      i64 2, label [[BRANCH_2:%.*]]
+; SWITCH-NEXT:      i64 4, label [[BRANCH_4:%.*]]
+; SWITCH-NEXT:      i64 6, label [[BRANCH_6:%.*]]
+; SWITCH-NEXT:    ]
+; SWITCH:       branch_0:
+; SWITCH-NEXT:    br label [[EXIT:%.*]]
+; SWITCH:       branch_2:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       branch_4:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       branch_6:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       default_branch:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       exit:
+; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ], [ 3, [[DEFAULT_BRANCH]] ]
+; SWITCH-NEXT:    ret i64 [[TMP2]]
+;
+  switch i64 %0, label %default_branch [
+  i64 0, label %branch_0
+  i64 2, label %branch_2
+  i64 4, label %branch_4
+  i64 6, label %branch_6
+  ]
+
+branch_0:
+  br label %exit
+
+branch_2:
+  br label %exit
+
+branch_4:
+  br label %exit
+
+branch_6:
+  br label %exit
+
+default_branch:
+  br label %exit
+
+exit:
+  %2 = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ], [ 3, %default_branch ]
+  ret i64 %2
+}
+
+define i64 @bar2(i64 %0) {
+; LOOKUPTABLE-LABEL: define i64 @bar2(
+; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
+; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT:%.*]] [
+; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0:%.*]]
+; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2:%.*]]
+; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4:%.*]]
+; LOOKUPTABLE-NEXT:      i64 6, label [[BRANCH_6:%.*]]
+; LOOKUPTABLE-NEXT:    ]
+; LOOKUPTABLE:       branch_0:
+; LOOKUPTABLE-NEXT:    br label [[EXIT:%.*]]
+; LOOKUPTABLE:       branch_2:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       branch_4:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       branch_6:
+; LOOKUPTABLE-NEXT:    br label [[EXIT]]
+; LOOKUPTABLE:       unreachabledefault:
+; LOOKUPTABLE-NEXT:    unreachable
+; LOOKUPTABLE:       exit:
+; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ]
+; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+;
+; SWITCH-LABEL: define i64 @bar2(
+; SWITCH-SAME: i64 [[TMP0:%.*]]) {
+; SWITCH-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT:%.*]] [
+; SWITCH-NEXT:      i64 0, label [[BRANCH_0:%.*]]
+; SWITCH-NEXT:      i64 2, label [[BRANCH_2:%.*]]
+; SWITCH-NEXT:      i64 4, label [[BRANCH_4:%.*]]
+; SWITCH-NEXT:      i64 6, label [[BRANCH_6:%.*]]
+; SWITCH-NEXT:    ]
+; SWITCH:       branch_0:
+; SWITCH-NEXT:    br label [[EXIT:%.*]]
+; SWITCH:       branch_2:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       branch_4:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       branch_6:
+; SWITCH-NEXT:    br label [[EXIT]]
+; SWITCH:       unreachabledefault:
+; SWITCH-NEXT:    unreachable
+; SWITCH:       exit:
+; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ]
+; SWITCH-NEXT:    ret i64 [[TMP2]]
+;
+  switch i64 %0, label %unreachabledefault [
+  i64 0, label %branch_0
+  i64 2, label %branch_2
+  i64 4, label %branch_4
+  i64 6, label %branch_6
+  ]
+
+branch_0:
+  br label %exit
+
+branch_2:
+  br label %exit
+
+branch_4:
+  br label %exit
+
+branch_6:
+  br label %exit
+
+unreachabledefault:
+  unreachable
+
+exit:
+  %2 = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ]
+  ret i64 %2
+}

>From fe59746686e2b635372cb8544f0f9e28f7262610 Mon Sep 17 00:00:00 2001
From: DianQK <dianqk at dianqk.net>
Date: Thu, 11 Jan 2024 19:05:03 +0800
Subject: [PATCH 2/6] [InlineCost] Consider the default branch when calculating
 cost

---
 .../llvm/Analysis/TargetTransformInfoImpl.h   |  4 +-
 llvm/include/llvm/CodeGen/BasicTTIImpl.h      | 12 +++---
 llvm/lib/Analysis/InlineCost.cpp              |  6 ++-
 .../Inline/inline-switch-default-2.ll         | 19 +--------
 .../Inline/inline-switch-default.ll           | 40 ++-----------------
 5 files changed, 19 insertions(+), 62 deletions(-)

diff --git a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
index 60eab53fa2f60..1bf9cec8a2c40 100644
--- a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
+++ b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
@@ -65,7 +65,9 @@ class TargetTransformInfoImplBase {
     (void)PSI;
     (void)BFI;
     JTSize = 0;
-    return SI.getNumCases();
+    bool HasDefault =
+        !isa<UnreachableInst>(SI.getDefaultDest()->getFirstNonPHIOrDbg());
+    return SI.getNumCases() + HasDefault;
   }
 
   unsigned getInliningThresholdMultiplier() const { return 1; }
diff --git a/llvm/include/llvm/CodeGen/BasicTTIImpl.h b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
index 5e7bdcdf72a49..45849869be4a6 100644
--- a/llvm/include/llvm/CodeGen/BasicTTIImpl.h
+++ b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
@@ -446,6 +446,8 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
     /// inline cost heuristic, but it's a generic cost model to be used in other
     /// places (e.g., in loop unrolling).
     unsigned N = SI.getNumCases();
+    bool HasDefault =
+        !isa<UnreachableInst>(SI.getDefaultDest()->getFirstNonPHIOrDbg());
     const TargetLoweringBase *TLI = getTLI();
     const DataLayout &DL = this->getDataLayout();
 
@@ -454,7 +456,7 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
 
     // Early exit if both a jump table and bit test are not allowed.
     if (N < 1 || (!IsJTAllowed && DL.getIndexSizeInBits(0u) < N))
-      return N;
+      return N + HasDefault;
 
     APInt MaxCaseVal = SI.case_begin()->getCaseValue()->getValue();
     APInt MinCaseVal = MaxCaseVal;
@@ -474,23 +476,23 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
 
       if (TLI->isSuitableForBitTests(Dests.size(), N, MinCaseVal, MaxCaseVal,
                                      DL))
-        return 1;
+        return 1 + HasDefault;
     }
 
     // Check if suitable for a jump table.
     if (IsJTAllowed) {
       if (N < 2 || N < TLI->getMinimumJumpTableEntries())
-        return N;
+        return N + HasDefault;
       uint64_t Range =
           (MaxCaseVal - MinCaseVal)
               .getLimitedValue(std::numeric_limits<uint64_t>::max() - 1) + 1;
       // Check whether a range of clusters is dense enough for a jump table
       if (TLI->isSuitableForJumpTable(&SI, N, Range, PSI, BFI)) {
         JumpTableSize = Range;
-        return 1;
+        return 1 + HasDefault;
       }
     }
-    return N;
+    return N + HasDefault;
   }
 
   bool shouldBuildLookupTables() {
diff --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
index 1fa7badaa4fa0..7b9e6e02f7b09 100644
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -707,8 +707,9 @@ class InlineCostCallAnalyzer final : public CallAnalyzer {
     if (JumpTableSize) {
       int64_t JTCost =
           static_cast<int64_t>(JumpTableSize) * InstrCost + 4 * InstrCost;
-
       addCost(JTCost);
+      if (NumCaseCluster > 1)
+        addCost((NumCaseCluster - 1) * 2 * InstrCost);
       return;
     }
 
@@ -1238,6 +1239,9 @@ class InlineCostFeaturesAnalyzer final : public CallAnalyzer {
       int64_t JTCost = static_cast<int64_t>(JumpTableSize) * InstrCost +
                        JTCostMultiplier * InstrCost;
       increment(InlineCostFeatureIndex::jump_table_penalty, JTCost);
+      if (NumCaseCluster > 1)
+        increment(InlineCostFeatureIndex::case_cluster_penalty,
+                  (NumCaseCluster - 1) * CaseClusterCostMultiplier * InstrCost);
       return;
     }
 
diff --git a/llvm/test/Transforms/Inline/inline-switch-default-2.ll b/llvm/test/Transforms/Inline/inline-switch-default-2.ll
index dd889124e3b5b..a784bd8d8613a 100644
--- a/llvm/test/Transforms/Inline/inline-switch-default-2.ll
+++ b/llvm/test/Transforms/Inline/inline-switch-default-2.ll
@@ -50,24 +50,7 @@ define i64 @foo1(i64 %0) {
 ;
 ; CHECK-LABEL: define i64 @foo1(
 ; CHECK-SAME: i64 [[TMP0:%.*]]) {
-; CHECK-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH_I:%.*]] [
-; CHECK-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
-; CHECK-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
-; CHECK-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
-; CHECK-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
-; CHECK-NEXT:    ]
-; CHECK:       branch_0.i:
-; CHECK-NEXT:    br label [[BAR1_EXIT:%.*]]
-; CHECK:       branch_2.i:
-; CHECK-NEXT:    br label [[BAR1_EXIT]]
-; CHECK:       branch_4.i:
-; CHECK-NEXT:    br label [[BAR1_EXIT]]
-; CHECK:       branch_6.i:
-; CHECK-NEXT:    br label [[BAR1_EXIT]]
-; CHECK:       default_branch.i:
-; CHECK-NEXT:    br label [[BAR1_EXIT]]
-; CHECK:       bar1.exit:
-; CHECK-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ], [ 3, [[DEFAULT_BRANCH_I]] ]
+; CHECK-NEXT:    [[TMP2:%.*]] = call i64 @bar1(i64 [[TMP0]])
 ; CHECK-NEXT:    ret i64 [[TMP2]]
 ;
   %2 = call i64 @bar1(i64 %0)
diff --git a/llvm/test/Transforms/Inline/inline-switch-default.ll b/llvm/test/Transforms/Inline/inline-switch-default.ll
index da95b9f5a458e..6271d6c06dcc6 100644
--- a/llvm/test/Transforms/Inline/inline-switch-default.ll
+++ b/llvm/test/Transforms/Inline/inline-switch-default.ll
@@ -5,51 +5,17 @@
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
-; FIXME: The `bar1` should not be inlined.
+; The `bar1` should not be inlined since there is a default branch.
 
 define i64 @foo1(i64 %0) {
 ; LOOKUPTABLE-LABEL: define i64 @foo1(
 ; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
-; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH_I:%.*]] [
-; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
-; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
-; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
-; LOOKUPTABLE-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
-; LOOKUPTABLE-NEXT:    ]
-; LOOKUPTABLE:       branch_0.i:
-; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT:%.*]]
-; LOOKUPTABLE:       branch_2.i:
-; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
-; LOOKUPTABLE:       branch_4.i:
-; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
-; LOOKUPTABLE:       branch_6.i:
-; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
-; LOOKUPTABLE:       default_branch.i:
-; LOOKUPTABLE-NEXT:    br label [[BAR1_EXIT]]
-; LOOKUPTABLE:       bar1.exit:
-; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ], [ 3, [[DEFAULT_BRANCH_I]] ]
+; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = call i64 @bar1(i64 [[TMP0]])
 ; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
 ;
 ; SWITCH-LABEL: define i64 @foo1(
 ; SWITCH-SAME: i64 [[TMP0:%.*]]) {
-; SWITCH-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH_I:%.*]] [
-; SWITCH-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
-; SWITCH-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
-; SWITCH-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
-; SWITCH-NEXT:      i64 6, label [[BRANCH_6_I:%.*]]
-; SWITCH-NEXT:    ]
-; SWITCH:       branch_0.i:
-; SWITCH-NEXT:    br label [[BAR1_EXIT:%.*]]
-; SWITCH:       branch_2.i:
-; SWITCH-NEXT:    br label [[BAR1_EXIT]]
-; SWITCH:       branch_4.i:
-; SWITCH-NEXT:    br label [[BAR1_EXIT]]
-; SWITCH:       branch_6.i:
-; SWITCH-NEXT:    br label [[BAR1_EXIT]]
-; SWITCH:       default_branch.i:
-; SWITCH-NEXT:    br label [[BAR1_EXIT]]
-; SWITCH:       bar1.exit:
-; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ], [ 3, [[DEFAULT_BRANCH_I]] ]
+; SWITCH-NEXT:    [[TMP2:%.*]] = call i64 @bar1(i64 [[TMP0]])
 ; SWITCH-NEXT:    ret i64 [[TMP2]]
 ;
   %2 = call i64 @bar1(i64 %0)

>From 2446d3c913d72af0cb734fb5552538209032c7d5 Mon Sep 17 00:00:00 2001
From: DianQK <dianqk at dianqk.net>
Date: Sun, 14 Jan 2024 22:17:03 +0800
Subject: [PATCH 3/6] fixup! [InlineCost] Consider the default branch when
 calculating cost

Add `defaultDestIsUnreachable`
---
 llvm/include/llvm/Analysis/TargetTransformInfoImpl.h | 3 +--
 llvm/include/llvm/CodeGen/BasicTTIImpl.h             | 3 +--
 llvm/include/llvm/IR/Instructions.h                  | 5 +++++
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
index 1bf9cec8a2c40..03baf2231e943 100644
--- a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
+++ b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
@@ -65,8 +65,7 @@ class TargetTransformInfoImplBase {
     (void)PSI;
     (void)BFI;
     JTSize = 0;
-    bool HasDefault =
-        !isa<UnreachableInst>(SI.getDefaultDest()->getFirstNonPHIOrDbg());
+    bool HasDefault = !SI.defaultDestIsUnreachable();
     return SI.getNumCases() + HasDefault;
   }
 
diff --git a/llvm/include/llvm/CodeGen/BasicTTIImpl.h b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
index 45849869be4a6..f019af9d4618a 100644
--- a/llvm/include/llvm/CodeGen/BasicTTIImpl.h
+++ b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
@@ -446,8 +446,7 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
     /// inline cost heuristic, but it's a generic cost model to be used in other
     /// places (e.g., in loop unrolling).
     unsigned N = SI.getNumCases();
-    bool HasDefault =
-        !isa<UnreachableInst>(SI.getDefaultDest()->getFirstNonPHIOrDbg());
+    bool HasDefault = !SI.defaultDestIsUnreachable();
     const TargetLoweringBase *TLI = getTLI();
     const DataLayout &DL = this->getDataLayout();
 
diff --git a/llvm/include/llvm/IR/Instructions.h b/llvm/include/llvm/IR/Instructions.h
index 4b5a4423b7689..e0d0397f6d984 100644
--- a/llvm/include/llvm/IR/Instructions.h
+++ b/llvm/include/llvm/IR/Instructions.h
@@ -49,6 +49,7 @@ class DataLayout;
 class StringRef;
 class Type;
 class Value;
+class UnreachableInst;
 
 //===----------------------------------------------------------------------===//
 //                                AllocaInst Class
@@ -3505,6 +3506,10 @@ class SwitchInst : public Instruction {
     return cast<BasicBlock>(getOperand(1));
   }
 
+  bool defaultDestIsUnreachable() const {
+    return isa<UnreachableInst>(getDefaultDest()->getFirstNonPHIOrDbg());
+  }
+
   void setDefaultDest(BasicBlock *DefaultCase) {
     setOperand(1, reinterpret_cast<Value*>(DefaultCase));
   }

>From 7ce42c05907812047d3488a34bbe397c7c7759c6 Mon Sep 17 00:00:00 2001
From: DianQK <dianqk at dianqk.net>
Date: Wed, 17 Jan 2024 21:00:09 +0800
Subject: [PATCH 4/6] fixup! [InlineCost] Consider the default branch when
 calculating cost

---
 llvm/include/llvm/Analysis/TargetTransformInfoImpl.h | 2 +-
 llvm/include/llvm/CodeGen/BasicTTIImpl.h             | 2 +-
 llvm/include/llvm/IR/Instructions.h                  | 4 +++-
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
index 03baf2231e943..0349c144d9723 100644
--- a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
+++ b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
@@ -65,7 +65,7 @@ class TargetTransformInfoImplBase {
     (void)PSI;
     (void)BFI;
     JTSize = 0;
-    bool HasDefault = !SI.defaultDestIsUnreachable();
+    bool HasDefault = !SI.defaultDestUndefined();
     return SI.getNumCases() + HasDefault;
   }
 
diff --git a/llvm/include/llvm/CodeGen/BasicTTIImpl.h b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
index f019af9d4618a..8152efdf60902 100644
--- a/llvm/include/llvm/CodeGen/BasicTTIImpl.h
+++ b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
@@ -446,7 +446,7 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
     /// inline cost heuristic, but it's a generic cost model to be used in other
     /// places (e.g., in loop unrolling).
     unsigned N = SI.getNumCases();
-    bool HasDefault = !SI.defaultDestIsUnreachable();
+    bool HasDefault = !SI.defaultDestUndefined();
     const TargetLoweringBase *TLI = getTLI();
     const DataLayout &DL = this->getDataLayout();
 
diff --git a/llvm/include/llvm/IR/Instructions.h b/llvm/include/llvm/IR/Instructions.h
index e0d0397f6d984..1db4ff2f09bca 100644
--- a/llvm/include/llvm/IR/Instructions.h
+++ b/llvm/include/llvm/IR/Instructions.h
@@ -3506,7 +3506,9 @@ class SwitchInst : public Instruction {
     return cast<BasicBlock>(getOperand(1));
   }
 
-  bool defaultDestIsUnreachable() const {
+  /// Returns true if the default branch must result in immediate undefined
+  /// behavior, false otherwise.
+  bool defaultDestUndefined() const {
     return isa<UnreachableInst>(getDefaultDest()->getFirstNonPHIOrDbg());
   }
 

>From 405a58f5609c14080e697f90e8ccaec7545c9e37 Mon Sep 17 00:00:00 2001
From: DianQK <dianqk at dianqk.net>
Date: Wed, 7 Feb 2024 08:06:08 +0800
Subject: [PATCH 5/6] fixup! Pre-commit test cases

---
 .../Inline/inline-switch-default-2.ll         | 58 ++++++------
 .../Inline/inline-switch-default.ll           | 88 +++++++++----------
 2 files changed, 73 insertions(+), 73 deletions(-)

diff --git a/llvm/test/Transforms/Inline/inline-switch-default-2.ll b/llvm/test/Transforms/Inline/inline-switch-default-2.ll
index a784bd8d8613a..8d3e24c798df8 100644
--- a/llvm/test/Transforms/Inline/inline-switch-default-2.ll
+++ b/llvm/test/Transforms/Inline/inline-switch-default-2.ll
@@ -3,7 +3,7 @@
 
 ; Check for scenarios without TTI.
 
-define i64 @foo1(i64 %0) {
+define i64 @foo1(i64 %a) {
 ; LOOKUPTABLE-LABEL: define i64 @foo1(
 ; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
 ; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH_I:%.*]] [
@@ -49,15 +49,15 @@ define i64 @foo1(i64 %0) {
 ; SWITCH-NEXT:    ret i64 [[TMP2]]
 ;
 ; CHECK-LABEL: define i64 @foo1(
-; CHECK-SAME: i64 [[TMP0:%.*]]) {
-; CHECK-NEXT:    [[TMP2:%.*]] = call i64 @bar1(i64 [[TMP0]])
-; CHECK-NEXT:    ret i64 [[TMP2]]
+; CHECK-SAME: i64 [[A:%.*]]) {
+; CHECK-NEXT:    [[B:%.*]] = call i64 @bar1(i64 [[A]])
+; CHECK-NEXT:    ret i64 [[B]]
 ;
-  %2 = call i64 @bar1(i64 %0)
-  ret i64 %2
+  %b = call i64 @bar1(i64 %a)
+  ret i64 %b
 }
 
-define i64 @foo2(i64 %0) {
+define i64 @foo2(i64 %a) {
 ; LOOKUPTABLE-LABEL: define i64 @foo2(
 ; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
 ; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT_I:%.*]] [
@@ -103,8 +103,8 @@ define i64 @foo2(i64 %0) {
 ; SWITCH-NEXT:    ret i64 [[TMP2]]
 ;
 ; CHECK-LABEL: define i64 @foo2(
-; CHECK-SAME: i64 [[TMP0:%.*]]) {
-; CHECK-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT_I:%.*]] [
+; CHECK-SAME: i64 [[A:%.*]]) {
+; CHECK-NEXT:    switch i64 [[A]], label [[UNREACHABLEDEFAULT_I:%.*]] [
 ; CHECK-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
 ; CHECK-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
 ; CHECK-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
@@ -121,14 +121,14 @@ define i64 @foo2(i64 %0) {
 ; CHECK:       unreachabledefault.i:
 ; CHECK-NEXT:    unreachable
 ; CHECK:       bar2.exit:
-; CHECK-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ]
-; CHECK-NEXT:    ret i64 [[TMP2]]
+; CHECK-NEXT:    [[B_I:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ]
+; CHECK-NEXT:    ret i64 [[B_I]]
 ;
-  %2 = call i64 @bar2(i64 %0)
-  ret i64 %2
+  %b = call i64 @bar2(i64 %a)
+  ret i64 %b
 }
 
-define i64 @bar1(i64 %0) {
+define i64 @bar1(i64 %a) {
 ; LOOKUPTABLE-LABEL: define i64 @bar1(
 ; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
 ; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH:%.*]] [
@@ -174,8 +174,8 @@ define i64 @bar1(i64 %0) {
 ; SWITCH-NEXT:    ret i64 [[TMP2]]
 ;
 ; CHECK-LABEL: define i64 @bar1(
-; CHECK-SAME: i64 [[TMP0:%.*]]) {
-; CHECK-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH:%.*]] [
+; CHECK-SAME: i64 [[A:%.*]]) {
+; CHECK-NEXT:    switch i64 [[A]], label [[DEFAULT_BRANCH:%.*]] [
 ; CHECK-NEXT:      i64 0, label [[BRANCH_0:%.*]]
 ; CHECK-NEXT:      i64 2, label [[BRANCH_2:%.*]]
 ; CHECK-NEXT:      i64 4, label [[BRANCH_4:%.*]]
@@ -192,10 +192,10 @@ define i64 @bar1(i64 %0) {
 ; CHECK:       default_branch:
 ; CHECK-NEXT:    br label [[EXIT]]
 ; CHECK:       exit:
-; CHECK-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ], [ 3, [[DEFAULT_BRANCH]] ]
-; CHECK-NEXT:    ret i64 [[TMP2]]
+; CHECK-NEXT:    [[B:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ], [ 3, [[DEFAULT_BRANCH]] ]
+; CHECK-NEXT:    ret i64 [[B]]
 ;
-  switch i64 %0, label %default_branch [
+  switch i64 %a, label %default_branch [
   i64 0, label %branch_0
   i64 2, label %branch_2
   i64 4, label %branch_4
@@ -218,11 +218,11 @@ default_branch:
   br label %exit
 
 exit:
-  %2 = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ], [ 3, %default_branch ]
-  ret i64 %2
+  %b = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ], [ 3, %default_branch ]
+  ret i64 %b
 }
 
-define i64 @bar2(i64 %0) {
+define i64 @bar2(i64 %a) {
 ; LOOKUPTABLE-LABEL: define i64 @bar2(
 ; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
 ; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT:%.*]] [
@@ -268,8 +268,8 @@ define i64 @bar2(i64 %0) {
 ; SWITCH-NEXT:    ret i64 [[TMP2]]
 ;
 ; CHECK-LABEL: define i64 @bar2(
-; CHECK-SAME: i64 [[TMP0:%.*]]) {
-; CHECK-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT:%.*]] [
+; CHECK-SAME: i64 [[A:%.*]]) {
+; CHECK-NEXT:    switch i64 [[A]], label [[UNREACHABLEDEFAULT:%.*]] [
 ; CHECK-NEXT:      i64 0, label [[BRANCH_0:%.*]]
 ; CHECK-NEXT:      i64 2, label [[BRANCH_2:%.*]]
 ; CHECK-NEXT:      i64 4, label [[BRANCH_4:%.*]]
@@ -286,10 +286,10 @@ define i64 @bar2(i64 %0) {
 ; CHECK:       unreachabledefault:
 ; CHECK-NEXT:    unreachable
 ; CHECK:       exit:
-; CHECK-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ]
-; CHECK-NEXT:    ret i64 [[TMP2]]
+; CHECK-NEXT:    [[B:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ]
+; CHECK-NEXT:    ret i64 [[B]]
 ;
-  switch i64 %0, label %unreachabledefault [
+  switch i64 %a, label %unreachabledefault [
   i64 0, label %branch_0
   i64 2, label %branch_2
   i64 4, label %branch_4
@@ -312,6 +312,6 @@ unreachabledefault:
   unreachable
 
 exit:
-  %2 = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ]
-  ret i64 %2
+  %b = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ]
+  ret i64 %b
 }
diff --git a/llvm/test/Transforms/Inline/inline-switch-default.ll b/llvm/test/Transforms/Inline/inline-switch-default.ll
index 6271d6c06dcc6..44f1304e82dff 100644
--- a/llvm/test/Transforms/Inline/inline-switch-default.ll
+++ b/llvm/test/Transforms/Inline/inline-switch-default.ll
@@ -7,25 +7,25 @@ target triple = "x86_64-unknown-linux-gnu"
 
 ; The `bar1` should not be inlined since there is a default branch.
 
-define i64 @foo1(i64 %0) {
+define i64 @foo1(i64 %a) {
 ; LOOKUPTABLE-LABEL: define i64 @foo1(
-; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
-; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = call i64 @bar1(i64 [[TMP0]])
-; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+; LOOKUPTABLE-SAME: i64 [[A:%.*]]) {
+; LOOKUPTABLE-NEXT:    [[B:%.*]] = call i64 @bar1(i64 [[A]])
+; LOOKUPTABLE-NEXT:    ret i64 [[B]]
 ;
 ; SWITCH-LABEL: define i64 @foo1(
-; SWITCH-SAME: i64 [[TMP0:%.*]]) {
-; SWITCH-NEXT:    [[TMP2:%.*]] = call i64 @bar1(i64 [[TMP0]])
-; SWITCH-NEXT:    ret i64 [[TMP2]]
+; SWITCH-SAME: i64 [[A:%.*]]) {
+; SWITCH-NEXT:    [[B:%.*]] = call i64 @bar1(i64 [[A]])
+; SWITCH-NEXT:    ret i64 [[B]]
 ;
-  %2 = call i64 @bar1(i64 %0)
-  ret i64 %2
+  %b = call i64 @bar1(i64 %a)
+  ret i64 %b
 }
 
-define i64 @foo2(i64 %0) {
+define i64 @foo2(i64 %a) {
 ; LOOKUPTABLE-LABEL: define i64 @foo2(
-; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
-; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT_I:%.*]] [
+; LOOKUPTABLE-SAME: i64 [[A:%.*]]) {
+; LOOKUPTABLE-NEXT:    switch i64 [[A]], label [[UNREACHABLEDEFAULT_I:%.*]] [
 ; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
 ; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
 ; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
@@ -42,12 +42,12 @@ define i64 @foo2(i64 %0) {
 ; LOOKUPTABLE:       unreachabledefault.i:
 ; LOOKUPTABLE-NEXT:    unreachable
 ; LOOKUPTABLE:       bar2.exit:
-; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ]
-; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+; LOOKUPTABLE-NEXT:    [[B_I:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ]
+; LOOKUPTABLE-NEXT:    ret i64 [[B_I]]
 ;
 ; SWITCH-LABEL: define i64 @foo2(
-; SWITCH-SAME: i64 [[TMP0:%.*]]) {
-; SWITCH-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT_I:%.*]] [
+; SWITCH-SAME: i64 [[A:%.*]]) {
+; SWITCH-NEXT:    switch i64 [[A]], label [[UNREACHABLEDEFAULT_I:%.*]] [
 ; SWITCH-NEXT:      i64 0, label [[BRANCH_0_I:%.*]]
 ; SWITCH-NEXT:      i64 2, label [[BRANCH_2_I:%.*]]
 ; SWITCH-NEXT:      i64 4, label [[BRANCH_4_I:%.*]]
@@ -64,17 +64,17 @@ define i64 @foo2(i64 %0) {
 ; SWITCH:       unreachabledefault.i:
 ; SWITCH-NEXT:    unreachable
 ; SWITCH:       bar2.exit:
-; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ]
-; SWITCH-NEXT:    ret i64 [[TMP2]]
+; SWITCH-NEXT:    [[B_I:%.*]] = phi i64 [ 5, [[BRANCH_0_I]] ], [ 9, [[BRANCH_2_I]] ], [ 2, [[BRANCH_4_I]] ], [ 7, [[BRANCH_6_I]] ]
+; SWITCH-NEXT:    ret i64 [[B_I]]
 ;
-  %2 = call i64 @bar2(i64 %0)
-  ret i64 %2
+  %b = call i64 @bar2(i64 %a)
+  ret i64 %b
 }
 
-define i64 @bar1(i64 %0) {
+define i64 @bar1(i64 %a) {
 ; LOOKUPTABLE-LABEL: define i64 @bar1(
-; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
-; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH:%.*]] [
+; LOOKUPTABLE-SAME: i64 [[A:%.*]]) {
+; LOOKUPTABLE-NEXT:    switch i64 [[A]], label [[DEFAULT_BRANCH:%.*]] [
 ; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0:%.*]]
 ; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2:%.*]]
 ; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4:%.*]]
@@ -91,12 +91,12 @@ define i64 @bar1(i64 %0) {
 ; LOOKUPTABLE:       default_branch:
 ; LOOKUPTABLE-NEXT:    br label [[EXIT]]
 ; LOOKUPTABLE:       exit:
-; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ], [ 3, [[DEFAULT_BRANCH]] ]
-; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+; LOOKUPTABLE-NEXT:    [[B:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ], [ 3, [[DEFAULT_BRANCH]] ]
+; LOOKUPTABLE-NEXT:    ret i64 [[B]]
 ;
 ; SWITCH-LABEL: define i64 @bar1(
-; SWITCH-SAME: i64 [[TMP0:%.*]]) {
-; SWITCH-NEXT:    switch i64 [[TMP0]], label [[DEFAULT_BRANCH:%.*]] [
+; SWITCH-SAME: i64 [[A:%.*]]) {
+; SWITCH-NEXT:    switch i64 [[A]], label [[DEFAULT_BRANCH:%.*]] [
 ; SWITCH-NEXT:      i64 0, label [[BRANCH_0:%.*]]
 ; SWITCH-NEXT:      i64 2, label [[BRANCH_2:%.*]]
 ; SWITCH-NEXT:      i64 4, label [[BRANCH_4:%.*]]
@@ -113,10 +113,10 @@ define i64 @bar1(i64 %0) {
 ; SWITCH:       default_branch:
 ; SWITCH-NEXT:    br label [[EXIT]]
 ; SWITCH:       exit:
-; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ], [ 3, [[DEFAULT_BRANCH]] ]
-; SWITCH-NEXT:    ret i64 [[TMP2]]
+; SWITCH-NEXT:    [[B:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ], [ 3, [[DEFAULT_BRANCH]] ]
+; SWITCH-NEXT:    ret i64 [[B]]
 ;
-  switch i64 %0, label %default_branch [
+  switch i64 %a, label %default_branch [
   i64 0, label %branch_0
   i64 2, label %branch_2
   i64 4, label %branch_4
@@ -139,14 +139,14 @@ default_branch:
   br label %exit
 
 exit:
-  %2 = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ], [ 3, %default_branch ]
-  ret i64 %2
+  %b = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ], [ 3, %default_branch ]
+  ret i64 %b
 }
 
-define i64 @bar2(i64 %0) {
+define i64 @bar2(i64 %a) {
 ; LOOKUPTABLE-LABEL: define i64 @bar2(
-; LOOKUPTABLE-SAME: i64 [[TMP0:%.*]]) {
-; LOOKUPTABLE-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT:%.*]] [
+; LOOKUPTABLE-SAME: i64 [[A:%.*]]) {
+; LOOKUPTABLE-NEXT:    switch i64 [[A]], label [[UNREACHABLEDEFAULT:%.*]] [
 ; LOOKUPTABLE-NEXT:      i64 0, label [[BRANCH_0:%.*]]
 ; LOOKUPTABLE-NEXT:      i64 2, label [[BRANCH_2:%.*]]
 ; LOOKUPTABLE-NEXT:      i64 4, label [[BRANCH_4:%.*]]
@@ -163,12 +163,12 @@ define i64 @bar2(i64 %0) {
 ; LOOKUPTABLE:       unreachabledefault:
 ; LOOKUPTABLE-NEXT:    unreachable
 ; LOOKUPTABLE:       exit:
-; LOOKUPTABLE-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ]
-; LOOKUPTABLE-NEXT:    ret i64 [[TMP2]]
+; LOOKUPTABLE-NEXT:    [[B:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ]
+; LOOKUPTABLE-NEXT:    ret i64 [[B]]
 ;
 ; SWITCH-LABEL: define i64 @bar2(
-; SWITCH-SAME: i64 [[TMP0:%.*]]) {
-; SWITCH-NEXT:    switch i64 [[TMP0]], label [[UNREACHABLEDEFAULT:%.*]] [
+; SWITCH-SAME: i64 [[A:%.*]]) {
+; SWITCH-NEXT:    switch i64 [[A]], label [[UNREACHABLEDEFAULT:%.*]] [
 ; SWITCH-NEXT:      i64 0, label [[BRANCH_0:%.*]]
 ; SWITCH-NEXT:      i64 2, label [[BRANCH_2:%.*]]
 ; SWITCH-NEXT:      i64 4, label [[BRANCH_4:%.*]]
@@ -185,10 +185,10 @@ define i64 @bar2(i64 %0) {
 ; SWITCH:       unreachabledefault:
 ; SWITCH-NEXT:    unreachable
 ; SWITCH:       exit:
-; SWITCH-NEXT:    [[TMP2:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ]
-; SWITCH-NEXT:    ret i64 [[TMP2]]
+; SWITCH-NEXT:    [[B:%.*]] = phi i64 [ 5, [[BRANCH_0]] ], [ 9, [[BRANCH_2]] ], [ 2, [[BRANCH_4]] ], [ 7, [[BRANCH_6]] ]
+; SWITCH-NEXT:    ret i64 [[B]]
 ;
-  switch i64 %0, label %unreachabledefault [
+  switch i64 %a, label %unreachabledefault [
   i64 0, label %branch_0
   i64 2, label %branch_2
   i64 4, label %branch_4
@@ -211,6 +211,6 @@ unreachabledefault:
   unreachable
 
 exit:
-  %2 = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ]
-  ret i64 %2
+  %b = phi i64 [ 5, %branch_0 ], [ 9, %branch_2 ], [ 2, %branch_4 ], [ 7, %branch_6 ]
+  ret i64 %b
 }

>From 1d2170ca03b2a89e28dd26d1145c7b560f07ce8f Mon Sep 17 00:00:00 2001
From: DianQK <dianqk at dianqk.net>
Date: Wed, 7 Feb 2024 08:40:39 +0800
Subject: [PATCH 6/6] fixup! [InlineCost] Consider the default branch when
 calculating cost

---
 .../llvm/Analysis/InlineModelFeatureMaps.h    |  2 ++
 .../llvm/Analysis/TargetTransformInfoImpl.h   |  3 +--
 llvm/include/llvm/CodeGen/BasicTTIImpl.h      | 11 ++++----
 llvm/lib/Analysis/InlineCost.cpp              | 25 ++++++++++---------
 4 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/llvm/include/llvm/Analysis/InlineModelFeatureMaps.h b/llvm/include/llvm/Analysis/InlineModelFeatureMaps.h
index ca9bb7244d669..d62ec9ce49119 100644
--- a/llvm/include/llvm/Analysis/InlineModelFeatureMaps.h
+++ b/llvm/include/llvm/Analysis/InlineModelFeatureMaps.h
@@ -39,6 +39,8 @@ namespace llvm {
   M(int64_t, {1}, jump_table_penalty, "Accumulation of costs for jump tables") \
   M(int64_t, {1}, case_cluster_penalty,                                        \
     "Accumulation of costs for case clusters")                                 \
+  M(int64_t, {1}, switch_default_dest_penalty,                                 \
+    "Accumulation of costs for switch default destination")                    \
   M(int64_t, {1}, switch_penalty,                                              \
     "Accumulation of costs for switch statements")                             \
   M(int64_t, {1}, unsimplified_common_instructions,                            \
diff --git a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
index 0349c144d9723..60eab53fa2f60 100644
--- a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
+++ b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
@@ -65,8 +65,7 @@ class TargetTransformInfoImplBase {
     (void)PSI;
     (void)BFI;
     JTSize = 0;
-    bool HasDefault = !SI.defaultDestUndefined();
-    return SI.getNumCases() + HasDefault;
+    return SI.getNumCases();
   }
 
   unsigned getInliningThresholdMultiplier() const { return 1; }
diff --git a/llvm/include/llvm/CodeGen/BasicTTIImpl.h b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
index 8152efdf60902..5e7bdcdf72a49 100644
--- a/llvm/include/llvm/CodeGen/BasicTTIImpl.h
+++ b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
@@ -446,7 +446,6 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
     /// inline cost heuristic, but it's a generic cost model to be used in other
     /// places (e.g., in loop unrolling).
     unsigned N = SI.getNumCases();
-    bool HasDefault = !SI.defaultDestUndefined();
     const TargetLoweringBase *TLI = getTLI();
     const DataLayout &DL = this->getDataLayout();
 
@@ -455,7 +454,7 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
 
     // Early exit if both a jump table and bit test are not allowed.
     if (N < 1 || (!IsJTAllowed && DL.getIndexSizeInBits(0u) < N))
-      return N + HasDefault;
+      return N;
 
     APInt MaxCaseVal = SI.case_begin()->getCaseValue()->getValue();
     APInt MinCaseVal = MaxCaseVal;
@@ -475,23 +474,23 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
 
       if (TLI->isSuitableForBitTests(Dests.size(), N, MinCaseVal, MaxCaseVal,
                                      DL))
-        return 1 + HasDefault;
+        return 1;
     }
 
     // Check if suitable for a jump table.
     if (IsJTAllowed) {
       if (N < 2 || N < TLI->getMinimumJumpTableEntries())
-        return N + HasDefault;
+        return N;
       uint64_t Range =
           (MaxCaseVal - MinCaseVal)
               .getLimitedValue(std::numeric_limits<uint64_t>::max() - 1) + 1;
       // Check whether a range of clusters is dense enough for a jump table
       if (TLI->isSuitableForJumpTable(&SI, N, Range, PSI, BFI)) {
         JumpTableSize = Range;
-        return 1 + HasDefault;
+        return 1;
       }
     }
-    return N + HasDefault;
+    return N;
   }
 
   bool shouldBuildLookupTables() {
diff --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
index 7b9e6e02f7b09..dc6878039f6a6 100644
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -336,8 +336,8 @@ class CallAnalyzer : public InstVisitor<CallAnalyzer, bool> {
 
   /// Called at the end of processing a switch instruction, with the given
   /// number of case clusters.
-  virtual void onFinalizeSwitch(unsigned JumpTableSize,
-                                unsigned NumCaseCluster) {}
+  virtual void onFinalizeSwitch(unsigned JumpTableSize, unsigned NumCaseCluster,
+                                bool DefaultDestUndefined) {}
 
   /// Called to account for any other instruction not specifically accounted
   /// for.
@@ -699,8 +699,10 @@ class InlineCostCallAnalyzer final : public CallAnalyzer {
                                        CallPenalty));
   }
 
-  void onFinalizeSwitch(unsigned JumpTableSize,
-                        unsigned NumCaseCluster) override {
+  void onFinalizeSwitch(unsigned JumpTableSize, unsigned NumCaseCluster,
+                        bool DefaultDestUndefined) override {
+    if (!DefaultDestUndefined)
+      addCost(2 * InstrCost);
     // If suitable for a jump table, consider the cost for the table size and
     // branch to destination.
     // Maximum valid cost increased in this function.
@@ -708,8 +710,6 @@ class InlineCostCallAnalyzer final : public CallAnalyzer {
       int64_t JTCost =
           static_cast<int64_t>(JumpTableSize) * InstrCost + 4 * InstrCost;
       addCost(JTCost);
-      if (NumCaseCluster > 1)
-        addCost((NumCaseCluster - 1) * 2 * InstrCost);
       return;
     }
 
@@ -1154,6 +1154,7 @@ class InlineCostFeaturesAnalyzer final : public CallAnalyzer {
   // heuristics in the ML inliner.
   static constexpr int JTCostMultiplier = 4;
   static constexpr int CaseClusterCostMultiplier = 2;
+  static constexpr int SwitchDefaultDestCostMultiplier = 2;
   static constexpr int SwitchCostMultiplier = 2;
 
   // FIXME: These are taken from the heuristic-based cost visitor: we should
@@ -1232,16 +1233,16 @@ class InlineCostFeaturesAnalyzer final : public CallAnalyzer {
     }
   }
 
-  void onFinalizeSwitch(unsigned JumpTableSize,
-                        unsigned NumCaseCluster) override {
+  void onFinalizeSwitch(unsigned JumpTableSize, unsigned NumCaseCluster,
+                        bool DefaultDestUndefined) override {
+    if (!DefaultDestUndefined)
+      increment(InlineCostFeatureIndex::switch_default_dest_penalty,
+                SwitchDefaultDestCostMultiplier * InstrCost);
 
     if (JumpTableSize) {
       int64_t JTCost = static_cast<int64_t>(JumpTableSize) * InstrCost +
                        JTCostMultiplier * InstrCost;
       increment(InlineCostFeatureIndex::jump_table_penalty, JTCost);
-      if (NumCaseCluster > 1)
-        increment(InlineCostFeatureIndex::case_cluster_penalty,
-                  (NumCaseCluster - 1) * CaseClusterCostMultiplier * InstrCost);
       return;
     }
 
@@ -2465,7 +2466,7 @@ bool CallAnalyzer::visitSwitchInst(SwitchInst &SI) {
   unsigned NumCaseCluster =
       TTI.getEstimatedNumberOfCaseClusters(SI, JumpTableSize, PSI, BFI);
 
-  onFinalizeSwitch(JumpTableSize, NumCaseCluster);
+  onFinalizeSwitch(JumpTableSize, NumCaseCluster, SI.defaultDestUndefined());
   return false;
 }
 



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