WholeProgramDevirt: Create bitcast to i8* at each virtual call site.

We can't reuse the llvm.assume instruction's bitcast because it may not
dominate every user of the vtable pointer.

Differential Revision: https://reviews.llvm.org/D36994

llvm-svn: 311491

5 files changed, 45 insertions, 0 deletions

diff --git a/llvm/test/Transforms/WholeProgramDevirt/import-no-dominating-assume.ll b/llvm/test/Transforms/WholeProgramDevirt/import-no-dominating-assume.ll
new file mode 100644
index 00000000000..b652ea4afe7
--- /dev/null
+++ b/llvm/test/Transforms/WholeProgramDevirt/import-no-dominating-assume.ll
@@ -0,0 +1,37 @@
+; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-vcp.yaml < %s | FileCheck %s
+
+target datalayout = "e-p:64:64"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @call1(i1 %a, i8* %obj) {
+  %vtableptr = bitcast i8* %obj to [3 x i8*]**
+  %vtable = load [3 x i8*]*, [3 x i8*]** %vtableptr
+  br i1 %a, label %bb1, label %bb2
+
+bb1:
+  ; CHECK: {{.*}} = bitcast {{.*}} to i8*
+  %vtablei8_1 = bitcast [3 x i8*]* %vtable to i8*
+  %p1 = call i1 @llvm.type.test(i8* %vtablei8_1, metadata !"typeid1")
+  call void @llvm.assume(i1 %p1)
+  %fptrptr1 = getelementptr [3 x i8*], [3 x i8*]* %vtable, i32 0, i32 0
+  %fptr1 = load i8*, i8** %fptrptr1
+  %fptr1_casted = bitcast i8* %fptr1 to i32 (i8*, i32)*
+  ; CHECK: {{.*}} = bitcast {{.*}} to i8*
+  %result1 = call i32 %fptr1_casted(i8* %obj, i32 1)
+  br label %bb2
+
+  ; CHECK: :
+bb2:
+  %vtablei8_2 = bitcast [3 x i8*]* %vtable to i8*
+  %p = call i1 @llvm.type.test(i8* %vtablei8_2, metadata !"typeid1")
+  call void @llvm.assume(i1 %p)
+  %fptrptr2 = getelementptr [3 x i8*], [3 x i8*]* %vtable, i32 0, i32 0
+  %fptr2 = load i8*, i8** %fptrptr2
+  %fptr2_casted = bitcast i8* %fptr2 to i32 (i8*, i32)*
+  ; CHECK: {{.*}} = bitcast {{.*}} to i8*
+  %result2 = call i32 %fptr2_casted(i8* %obj, i32 1)
+  ret i32 %result2
+}
+
+declare void @llvm.assume(i1)
+declare i1 @llvm.type.test(i8*, metadata)
diff --git a/llvm/test/Transforms/WholeProgramDevirt/import.ll b/llvm/test/Transforms/WholeProgramDevirt/import.ll
index 7f34b04ce11..18f048fd06c 100644
--- a/llvm/test/Transforms/WholeProgramDevirt/import.ll
+++ b/llvm/test/Transforms/WholeProgramDevirt/import.ll
@@ -29,6 +29,7 @@ define i32 @call1(i8* %obj) {
   ; SINGLE-IMPL: call i32 bitcast (void ()* @singleimpl1 to i32 (i8*, i32)*)
   %result = call i32 %fptr_casted(i8* %obj, i32 1)
   ; UNIFORM-RET-VAL: ret i32 42
+  ; VCP: {{.*}} = bitcast {{.*}} to i8*
   ; VCP: [[VT1:%.*]] = bitcast {{.*}} to i8*
   ; VCP: [[GEP1:%.*]] = getelementptr i8, i8* [[VT1]], i32 ptrtoint (i8* @__typeid_typeid1_0_1_byte to i32)
   ; VCP: [[BC1:%.*]] = bitcast i8* [[GEP1]] to i32*
diff --git a/llvm/test/Transforms/WholeProgramDevirt/unique-retval.ll b/llvm/test/Transforms/WholeProgramDevirt/unique-retval.ll
index e9ae176fe8a..4452bb75d03 100644
--- a/llvm/test/Transforms/WholeProgramDevirt/unique-retval.ll
+++ b/llvm/test/Transforms/WholeProgramDevirt/unique-retval.ll
@@ -20,6 +20,7 @@ define i1 @vf1(i8* %this) readnone {
 define i1 @call1(i8* %obj) {
   %vtableptr = bitcast i8* %obj to [1 x i8*]**
   %vtable = load [1 x i8*]*, [1 x i8*]** %vtableptr
+  ; CHECK: {{.*}} = bitcast [1 x i8*]* {{.*}} to i8*
   ; CHECK: [[VT1:%[^ ]*]] = bitcast [1 x i8*]* {{.*}} to i8*
   %vtablei8 = bitcast [1 x i8*]* %vtable to i8*
   %p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"typeid1")
diff --git a/llvm/test/Transforms/WholeProgramDevirt/virtual-const-prop-begin.ll b/llvm/test/Transforms/WholeProgramDevirt/virtual-const-prop-begin.ll
index 080ed6caac5..63549e8540c 100644
--- a/llvm/test/Transforms/WholeProgramDevirt/virtual-const-prop-begin.ll
+++ b/llvm/test/Transforms/WholeProgramDevirt/virtual-const-prop-begin.ll
@@ -71,6 +71,7 @@ define i32 @vf4i32(i8* %this) readnone {
 define i1 @call1(i8* %obj) {
   %vtableptr = bitcast i8* %obj to [3 x i8*]**
   %vtable = load [3 x i8*]*, [3 x i8*]** %vtableptr
+  ; CHECK: {{.*}} = bitcast [3 x i8*]* {{.*}} to i8*
   ; CHECK: [[VT1:%[^ ]*]] = bitcast [3 x i8*]* {{.*}} to i8*
   %vtablei8 = bitcast [3 x i8*]* %vtable to i8*
   %p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"typeid")
@@ -91,6 +92,7 @@ define i1 @call1(i8* %obj) {
 define i1 @call2(i8* %obj) {
   %vtableptr = bitcast i8* %obj to [3 x i8*]**
   %vtable = load [3 x i8*]*, [3 x i8*]** %vtableptr
+  ; CHECK: {{.*}} = bitcast [3 x i8*]* {{.*}} to i8*
   ; CHECK: [[VT2:%[^ ]*]] = bitcast [3 x i8*]* {{.*}} to i8*
   %vtablei8 = bitcast [3 x i8*]* %vtable to i8*
   %p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"typeid")
@@ -111,6 +113,7 @@ define i1 @call2(i8* %obj) {
 define i32 @call3(i8* %obj) {
   %vtableptr = bitcast i8* %obj to [3 x i8*]**
   %vtable = load [3 x i8*]*, [3 x i8*]** %vtableptr
+  ; CHECK: {{.*}} = bitcast [3 x i8*]* {{.*}} to i8*
   ; CHECK: [[VT3:%[^ ]*]] = bitcast [3 x i8*]* {{.*}} to i8*
   %vtablei8 = bitcast [3 x i8*]* %vtable to i8*
   %p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"typeid")
diff --git a/llvm/test/Transforms/WholeProgramDevirt/virtual-const-prop-end.ll b/llvm/test/Transforms/WholeProgramDevirt/virtual-const-prop-end.ll
index 14360c78d95..3d61e1e2082 100644
--- a/llvm/test/Transforms/WholeProgramDevirt/virtual-const-prop-end.ll
+++ b/llvm/test/Transforms/WholeProgramDevirt/virtual-const-prop-end.ll
@@ -66,6 +66,7 @@ define i32 @vf4i32(i8* %this) readnone {
 define i1 @call1(i8* %obj) {
   %vtableptr = bitcast i8* %obj to [3 x i8*]**
   %vtable = load [3 x i8*]*, [3 x i8*]** %vtableptr
+  ; CHECK: {{.*}} = bitcast [3 x i8*]* {{.*}} to i8*
   ; CHECK: [[VT1:%[^ ]*]] = bitcast [3 x i8*]* {{.*}} to i8*
   %vtablei8 = bitcast [3 x i8*]* %vtable to i8*
   %p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"typeid")
@@ -86,6 +87,7 @@ define i1 @call1(i8* %obj) {
 define i1 @call2(i8* %obj) {
   %vtableptr = bitcast i8* %obj to [3 x i8*]**
   %vtable = load [3 x i8*]*, [3 x i8*]** %vtableptr
+  ; CHECK: {{.*}} = bitcast [3 x i8*]* {{.*}} to i8*
   ; CHECK: [[VT2:%[^ ]*]] = bitcast [3 x i8*]* {{.*}} to i8*
   %vtablei8 = bitcast [3 x i8*]* %vtable to i8*
   %p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"typeid")
@@ -106,6 +108,7 @@ define i1 @call2(i8* %obj) {
 define i32 @call3(i8* %obj) {
   %vtableptr = bitcast i8* %obj to [3 x i8*]**
   %vtable = load [3 x i8*]*, [3 x i8*]** %vtableptr
+  ; CHECK: {{.*}} = bitcast [3 x i8*]* {{.*}} to i8*
   ; CHECK: [[VT3:%[^ ]*]] = bitcast [3 x i8*]* {{.*}} to i8*
   %vtablei8 = bitcast [3 x i8*]* %vtable to i8*
   %p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"typeid")