[InlineCost] Tracking Values through PHI Nodes

This patch fix this FIXME in visitPHI()

FIXME: We should potentially be tracking values through phi nodes,
especially when they collapse to a single value due to deleted CFG edges
during inlining.

Differential Revision: https://reviews.llvm.org/D38594

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320699 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 504 insertions, 0 deletions

diff --git a/test/Transforms/Inline/AArch64/phi.ll b/test/Transforms/Inline/AArch64/phi.ll
new file mode 100644
index 00000000000..63999f58b2c
--- /dev/null
+++ b/test/Transforms/Inline/AArch64/phi.ll
@@ -0,0 +1,504 @@
+; RUN: opt -inline -mtriple=aarch64--linux-gnu -S -o - < %s -inline-threshold=0 | FileCheck %s
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64--linux-gnu"
+
+declare void @pad()
+@glbl = external global i32
+
+define i1 @outer1() {
+; CHECK-LABEL: @outer1(
+; CHECK-NOT: call i1 @inner1
+  %C = call i1 @inner1()
+  ret i1 %C
+}
+
+define i1 @inner1() {
+entry:
+  br label %if_true
+
+if_true:
+  %phi = phi i1 [0, %entry], [%phi, %if_true] ; Simplified to 0
+  br i1 %phi, label %if_true, label %exit
+
+exit:
+  store i32 0, i32* @glbl
+  store i32 1, i32* @glbl
+  store i32 2, i32* @glbl
+  store i32 3, i32* @glbl
+  store i32 4, i32* @glbl
+  ret i1 %phi
+}
+
+
+define i1 @outer2(i1 %val) {
+; CHECK-LABEL: @outer2(
+; CHECK: call i1 @inner2
+  %C = call i1 @inner2(i1 %val)
+  ret i1 %C
+}
+
+define i1 @inner2(i1 %val) {
+entry:
+  br label %if_true
+
+if_true:
+  %phi = phi i1 [%val, %entry], [%phi, %if_true] ; Cannot be simplified to a constant
+  br i1 %phi, label %if_true, label %exit
+
+exit:
+  call void @pad()
+  ret i1 %phi
+}
+
+
+define i1 @outer3(i1 %cond) {
+; CHECK-LABEL: @outer3(
+; CHECK-NOT: call i1 @inner3
+  %C = call i1 @inner3(i1 %cond)
+  ret i1 %C
+}
+
+define i1 @inner3(i1 %cond) {
+entry:
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  br label %exit
+
+exit:
+  %phi = phi i32 [0, %entry], [0, %if_true] ; Simplified to 0
+  %cmp = icmp eq i32 %phi, 0
+  store i32 0, i32* @glbl
+  store i32 1, i32* @glbl
+  store i32 2, i32* @glbl
+  store i32 3, i32* @glbl
+  store i32 4, i32* @glbl
+  ret i1 %cmp
+}
+
+
+define i1 @outer4(i1 %cond) {
+; CHECK-LABEL: @outer4(
+; CHECK-NOT: call i1 @inner4
+  %C = call i1 @inner4(i1 %cond, i32 0)
+  ret i1 %C
+}
+
+define i1 @inner4(i1 %cond, i32 %val) {
+entry:
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  br label %exit
+
+exit:
+  %phi = phi i32 [0, %entry], [%val, %if_true] ; Simplified to 0
+  %cmp = icmp eq i32 %phi, 0
+  call void @pad()
+  ret i1 %cmp
+}
+
+
+define i1 @outer5_1(i1 %cond) {
+; CHECK-LABEL: @outer5_1(
+; CHECK-NOT: call i1 @inner5
+  %C = call i1 @inner5(i1 %cond, i32 0, i32 0)
+  ret i1 %C
+}
+
+
+define i1 @outer5_2(i1 %cond) {
+; CHECK-LABEL: @outer5_2(
+; CHECK: call i1 @inner5
+  %C = call i1 @inner5(i1 %cond, i32 0, i32 1)
+  ret i1 %C
+}
+
+define i1 @inner5(i1 %cond, i32 %val1, i32 %val2) {
+entry:
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  br label %exit
+
+exit:
+  %phi = phi i32 [%val1, %entry], [%val2, %if_true] ; Can be simplified to a constant if %val1 and %val2 are the same constants
+  %cmp = icmp eq i32 %phi, 0
+  call void @pad()
+  store i32 0, i32* @glbl
+  ret i1 %cmp
+}
+
+
+define i1 @outer6(i1 %cond, i32 %val) {
+; CHECK-LABEL: @outer6(
+; CHECK-NOT: call i1 @inner6
+  %C = call i1 @inner6(i1 true, i32 %val, i32 0)
+  ret i1 %C
+}
+
+define i1 @inner6(i1 %cond, i32 %val1, i32 %val2) {
+entry:
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  br label %exit
+
+exit:
+  %phi = phi i32 [%val1, %entry], [%val2, %if_true] ; Simplified to 0
+  %cmp = icmp eq i32 %phi, 0
+  call void @pad()
+  store i32 0, i32* @glbl
+  store i32 1, i32* @glbl
+  ret i1 %cmp
+}
+
+
+define i1 @outer7(i1 %cond, i32 %val) {
+; CHECK-LABEL: @outer7(
+; CHECK-NOT: call i1 @inner7
+  %C = call i1 @inner7(i1 false, i32 0, i32 %val)
+  ret i1 %C
+}
+
+define i1 @inner7(i1 %cond, i32 %val1, i32 %val2) {
+entry:
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  br label %exit
+
+exit:
+  %phi = phi i32 [%val1, %entry], [%val2, %if_true] ; Simplified to 0
+  %cmp = icmp eq i32 %phi, 0
+  call void @pad()
+  store i32 0, i32* @glbl
+  store i32 1, i32* @glbl
+  ret i1 %cmp
+}
+
+
+define i1 @outer8_1() {
+; CHECK-LABEL: @outer8_1(
+; CHECK-NOT: call i1 @inner8
+  %C = call i1 @inner8(i32 0)
+  ret i1 %C
+}
+
+
+
+define i1 @outer8_2() {
+; CHECK-LABEL: @outer8_2(
+; CHECK-NOT: call i1 @inner8
+  %C = call i1 @inner8(i32 3)
+  ret i1 %C
+}
+
+define i1 @inner8(i32 %cond) {
+entry:
+  switch i32 %cond, label %default [ i32 0, label %zero
+                                     i32 1, label %one
+                                     i32 2, label %two ]
+
+zero:
+  br label %exit
+
+one:
+  br label %exit
+
+two:
+  br label %exit
+
+default:
+  br label %exit
+
+exit:
+  %phi = phi i32 [0, %zero], [1, %one], [2, %two], [-1, %default] ; Can be simplified to a constant if the switch condition is known
+  %cmp = icmp eq i32 %phi, 0
+  call void @pad()
+  ret i1 %cmp
+}
+
+
+define i1 @outer9(i1 %cond) {
+; CHECK-LABEL: @outer9(
+; CHECK-NOT: call i1 @inner9
+  %C = call i1 @inner9(i32 0, i1 %cond)
+  ret i1 %C
+}
+
+define i1 @inner9(i32 %cond1, i1 %cond2) {
+entry:
+  switch i32 %cond1, label %exit [ i32 0, label %zero
+                                   i32 1, label %one
+                                   i32 2, label %two ]
+
+zero:
+  br label %exit
+
+one:
+  br label %exit
+
+two:
+  br i1 %cond2, label %two_true, label %two_false
+
+two_true:
+  br label %exit
+
+two_false:
+  br label %exit
+
+exit:
+  %phi = phi i32 [0, %zero], [1, %one], [2, %two_true], [2, %two_false], [-1, %entry] ; Simplified to 0
+  %cmp = icmp eq i32 %phi, 0
+  call void @pad()
+  store i32 0, i32* @glbl
+  ret i1 %cmp
+}
+
+
+define i32 @outer10(i1 %cond) {
+; CHECK-LABEL: @outer10(
+; CHECK-NOT: call i32 @inner10
+  %A = alloca i32
+  %C = call i32 @inner10(i1 %cond, i32* %A)
+  ret i32 %C
+}
+
+define i32 @inner10(i1 %cond, i32* %A) {
+entry:
+  br label %if_true
+
+if_true:
+  %phi = phi i32* [%A, %entry], [%phi, %if_true] ; Simplified to %A
+  %load = load i32, i32* %phi
+  br i1 %cond, label %if_true, label %exit
+
+exit:
+  call void @pad()
+  ret i32 %load
+}
+
+
+define i32 @outer11(i1 %cond, i32* %ptr) {
+; CHECK-LABEL: @outer11(
+; CHECK: call i32 @inner11
+  %C = call i32 @inner11(i1 %cond, i32* %ptr)
+  ret i32 %C
+}
+
+define i32 @inner11(i1 %cond, i32* %ptr) {
+entry:
+  br label %if_true
+
+if_true:
+  %phi = phi i32* [%ptr, %entry], [%phi, %if_true] ; Cannot be simplified
+  %load = load i32, i32* %phi
+  br i1 %cond, label %if_true, label %exit
+
+exit:
+  call void @pad()
+  ret i32 %load
+}
+
+
+define i32 @outer12(i1 %cond) {
+; CHECK-LABEL: @outer12(
+; CHECK-NOT: call i32 @inner12
+  %A = alloca i32
+  %C = call i32 @inner12(i1 %cond, i32* %A)
+  ret i32 %C
+}
+
+define i32 @inner12(i1 %cond, i32* %ptr) {
+entry:
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  br label %exit
+
+exit:
+  %phi = phi i32* [%ptr, %entry], [%ptr, %if_true] ; Simplified to %A
+  %load = load i32, i32* %phi
+  call void @pad()
+  ret i32 %load
+}
+
+
+define i32 @outer13(i1 %cond) {
+; CHECK-LABEL: @outer13(
+; CHECK-NOT: call i32 @inner13
+  %A = alloca i32
+  %C = call i32 @inner13(i1 %cond, i32* %A)
+  ret i32 %C
+}
+
+define i32 @inner13(i1 %cond, i32* %ptr) {
+entry:
+  %gep1 = getelementptr inbounds i32, i32* %ptr, i32 2
+  %gep2 = getelementptr inbounds i32, i32* %ptr, i32 1
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  %gep3 = getelementptr inbounds i32, i32* %gep2, i32 1
+  br label %exit
+
+exit:
+  %phi = phi i32* [%gep1, %entry], [%gep3, %if_true] ; Simplifeid to %gep1
+  %load = load i32, i32* %phi
+  call void @pad()
+  ret i32 %load
+}
+
+
+define i32 @outer14(i1 %cond) {
+; CHECK-LABEL: @outer14(
+; CHECK: call i32 @inner14
+  %A1 = alloca i32
+  %A2 = alloca i32
+  %C = call i32 @inner14(i1 %cond, i32* %A1, i32* %A2)
+  ret i32 %C
+}
+
+define i32 @inner14(i1 %cond, i32* %ptr1, i32* %ptr2) {
+entry:
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  br label %exit
+
+exit:
+  %phi = phi i32* [%ptr1, %entry], [%ptr2, %if_true] ; Cannot be simplified
+  %load = load i32, i32* %phi
+  call void @pad()
+  store i32 0, i32* @glbl
+  ret i32 %load
+}
+
+
+define i32 @outer15(i1 %cond, i32* %ptr) {
+; CHECK-LABEL: @outer15(
+; CHECK-NOT: call i32 @inner15
+  %A = alloca i32
+  %C = call i32 @inner15(i1 true, i32* %ptr, i32* %A)
+  ret i32 %C
+}
+
+define i32 @inner15(i1 %cond, i32* %ptr1, i32* %ptr2) {
+entry:
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  br label %exit
+
+exit:
+  %phi = phi i32* [%ptr1, %entry], [%ptr2, %if_true] ; Simplified to %A
+  %load = load i32, i32* %phi
+  call void @pad()
+  store i32 0, i32* @glbl
+  store i32 1, i32* @glbl
+  ret i32 %load
+}
+
+
+define i32 @outer16(i1 %cond, i32* %ptr) {
+; CHECK-LABEL: @outer16(
+; CHECK-NOT: call i32 @inner16
+  %A = alloca i32
+  %C = call i32 @inner16(i1 false, i32* %A, i32* %ptr)
+  ret i32 %C
+}
+
+define i32 @inner16(i1 %cond, i32* %ptr1, i32* %ptr2) {
+entry:
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  br label %exit
+
+exit:
+  %phi = phi i32* [%ptr1, %entry], [%ptr2, %if_true] ; Simplified to %A
+  %load = load i32, i32* %phi
+  call void @pad()
+  store i32 0, i32* @glbl
+  store i32 1, i32* @glbl
+  ret i32 %load
+}
+
+
+define i1 @outer17(i1 %cond) {
+; CHECK-LABEL: @outer17(
+; CHECK: call i1 @inner17
+  %A = alloca i32
+  %C = call i1 @inner17(i1 %cond, i32* %A)
+  ret i1 %C
+}
+
+define i1 @inner17(i1 %cond, i32* %ptr) {
+entry:
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  br label %exit
+
+exit:
+  %phi = phi i32* [null, %entry], [%ptr, %if_true] ; Cannot be mapped to a constant
+  %cmp = icmp eq i32* %phi, null
+  call void @pad()
+  ret i1 %cmp
+}
+
+
+define i1 @outer18(i1 %cond) {
+; CHECK-LABEL: @outer18(
+; CHECK-NOT: call i1 @inner18
+  %C = call i1 @inner18(i1 %cond, i1 true)
+  ret i1 %C
+}
+
+define i1 @inner18(i1 %cond1, i1 %cond2) {
+entry:
+  br i1 %cond1, label %block1, label %block2
+
+block1:
+  br i1 %cond2, label %block3, label %block4
+
+block2:
+  br i1 %cond2, label %block5, label %block4
+
+block3:
+  %phi = phi i32 [0, %block1], [1, %block4], [0, %block5] ; Simplified to 0
+  %cmp = icmp eq i32 %phi, 0
+  call void @pad()
+  ret i1 %cmp
+
+block4:                                                   ; Unreachable block
+  br label %block3
+
+block5:
+  br label %block3
+}
+
+
+define i1 @outer19(i1 %cond) {
+; CHECK-LABEL: @outer19(
+; CHECK: call i1 @inner19
+  %A = alloca i32
+  %C = call i1 @inner19(i1 %cond, i32* %A)
+  ret i1 %C
+}
+
+define i1 @inner19(i1 %cond, i32* %ptr) {
+entry:
+  br i1 %cond, label %if_true, label %exit
+
+if_true:
+  br label %exit
+
+exit:
+  %phi = phi i32* [%ptr, %entry], [null, %if_true] ; Cannot be mapped to a constant
+  %cmp = icmp eq i32* %phi, null
+  call void @pad()
+  ret i1 %cmp
+}