[IRSim][IROutliner] Allowing GEP instructions to be outlined.

[AndrewLitteken]

Summary

We outline what the IRSimilarityIdentifier deems GEP Instructions to be similar. In this case, the types must be the same, and the operand values after the first indexing operand must be the exact same.

Tests:

• Removing test/Transforms/IROutliner/illegal-gep.ll
• Adding test/Transforms/IROutliner/outlining-gep.ll

[jroelofs]

LGTM

llvm/include/llvm/Transforms/IPO/IROutliner.h

struct InstructionAllowed : public InstVisitor<InstructionAllowed, bool> {
     // We exclude all exception handling cases since they are so context
     // dependent.
     bool visitLandingPadInst(LandingPadInst &LPI) { return false; }
     bool visitFuncletPadInst(FuncletPadInst &FPI) { return false; }
     // DebugInfo should be included in the regions, but should not be
     // analyzed for similarity as it has no bearing on the outcome of the
     // program.
     bool visitDbgInfoIntrinsic(DbgInfoIntrinsic &DII) { return true; }
-    // TODO: Handle GetElementPtrInsts
-    bool visitGetElementPtrInst(GetElementPtrInst &GEPI) { return false; }
     // TODO: Handle specific intrinsics individually from those that can be
     // handled.
     bool IntrinsicInst(IntrinsicInst &II) { return false; }
     // TODO: Handle CallInsts, there will need to be handling for special kinds
     // of calls, as well as calls to intrinsics.
     bool visitCallInst(CallInst &CI) { return false; }
     // TODO: Handle FreezeInsts.  Since a frozen value could be frozen inside
     // the outlined region, and then returned as an output, this will have to be

llvm/test/Transforms/IROutliner/illegal-gep.ll

-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -verify -iroutliner < %s | FileCheck %s
-
-; This test checks to make sure that we do not outline getelementptr
-; instructions since we must make extra checks on the final operands.
-
-%struct.RT = type { i8, [10 x [20 x i32]], i8 }
-%struct.ST = type { i32, double, %struct.RT }
-
-define void @function1(%struct.ST* %s, i64 %t) {
-; CHECK-LABEL: @function1(
-; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]])
-; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr inbounds [[STRUCT_ST:%.*]], %struct.ST* [[S:%.*]], i64 1
-; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds [[STRUCT_ST]], %struct.ST* [[S]], i64 [[T:%.*]]
-; CHECK-NEXT:    ret void
-;
-entry:
-  %a = alloca i32, align 4
-  %b = alloca i32, align 4
-  store i32 2, i32* %a, align 4
-  store i32 3, i32* %b, align 4
-  %0 = getelementptr inbounds %struct.ST, %struct.ST* %s, i64 1
-  %1 = getelementptr inbounds %struct.ST, %struct.ST* %s, i64 %t
-  ret void
-}
-
-define void @function2(%struct.ST* %s, i64 %t) {
-; CHECK-LABEL: @function2(
-; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
-; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]])
-; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr inbounds [[STRUCT_ST:%.*]], %struct.ST* [[S:%.*]], i64 1
-; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds [[STRUCT_ST]], %struct.ST* [[S]], i64 [[T:%.*]]
-; CHECK-NEXT:    ret void
-;
-entry:
-  %a = alloca i32, align 4
-  %b = alloca i32, align 4
-  store i32 2, i32* %a, align 4
-  store i32 3, i32* %b, align 4
-  %0 = getelementptr inbounds %struct.ST, %struct.ST* %s, i64 1
-  %1 = getelementptr inbounds %struct.ST, %struct.ST* %s, i64 %t
-  ret void
-}

llvm/test/Transforms/IROutliner/outlining-gep.ll

+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -verify -iroutliner < %s | FileCheck %s
+
+; This test checks to make sure that we outline getelementptr instructions only
+; when all the operands after the first are the exact same. In this case, we
+; outline from the first two functions, but not the third.
+
+%struct.RT = type { i8, [10 x [20 x i32]], i8 }
+%struct.ST = type { i32, double, %struct.RT }
+
+define void @function1(%struct.ST* %s, i64 %t) {
+; CHECK-LABEL: @function1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], %struct.ST* [[S:%.*]], i64 [[T:%.*]])
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  %0 = getelementptr inbounds %struct.ST, %struct.ST* %s, i64 %t, i32 1
+  ret void
+}
+
+define void @function2(%struct.ST* %s, i64 %t) {
+; CHECK-LABEL: @function2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], %struct.ST* [[S:%.*]], i64 [[T:%.*]])
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  %0 = getelementptr inbounds %struct.ST, %struct.ST* %s, i64 %t, i32 1
+  ret void
+}
+
+define void @function3(%struct.ST* %s, i64 %t) {
+; CHECK-LABEL: @function3(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    store i32 2, i32* [[A]], align 4
+; CHECK-NEXT:    store i32 3, i32* [[B]], align 4
+; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr inbounds [[STRUCT_ST:%.*]], %struct.ST* [[S:%.*]], i64 [[T:%.*]], i32 0
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  %0 = getelementptr inbounds %struct.ST, %struct.ST* %s, i64 %t, i32 0
+  ret void
+}
+
+; CHECK: define internal void @outlined_ir_func_0(i32* [[ARG0:%.*]], i32* [[ARG1:%.*]], %struct.ST* [[ARG2:%.*]], i64 [[ARG3:%.*]])
+; CHECK: entry_to_outline:
+; CHECK-NEXT:    store i32 2, i32* [[ARG0]], align 4
+; CHECK-NEXT:    store i32 3, i32* [[ARG1]], align 4
+; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr inbounds %struct.ST, %struct.ST* [[ARG2]], i64 [[ARG3]], i32 1