Adding a width of the GEP index to the Data Layout.

Making a width of GEP Index, which is used for address calculation, to be one of the pointer properties in the Data Layout.
p[address space]:size:memory_size:alignment:pref_alignment:index_size_in_bits.
The index size parameter is optional, if not specified, it is equal to the pointer size.

Till now, the InstCombiner normalized GEPs and extended the Index operand to the pointer width.
It works fine if you can convert pointer to integer for address calculation and all registered targets do this.
But some ISAs have very restricted instruction set for the pointer calculation. During discussions were desided to retrieve information for GEP index from the Data Layout.
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120416.html

I added an interface to the Data Layout and I changed the InstCombiner and some other passes to take the Index width into account.
This change does not affect any in-tree target. I added tests to cover data layouts with explicitly specified index size.

Differential Revision: https://reviews.llvm.org/D42123

llvm-svn: 325102

1 files changed, 155 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/gep-custom-dl.ll b/llvm/test/Transforms/InstCombine/gep-custom-dl.ll
new file mode 100644
index 00000000000..7c489e98814
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/gep-custom-dl.ll
@@ -0,0 +1,155 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-m:m-p:40:64:64:32-i32:32-i16:16-i8:8-n32"
+
+%struct.B = type { double }
+%struct.A = type { %struct.B, i32, i32 }
+%struct.C = type { [7 x i8] }
+
+
+@Global = constant [10 x i8] c"helloworld"
+
+
+; Test that two array indexing geps fold
+define i32* @test1(i32* %I) {
+; CHECK-LABEL: @test1(
+; CHECK-NEXT:    [[B:%.*]] = getelementptr i32, i32* [[I:%.*]], i32 21
+; CHECK-NEXT:    ret i32* [[B]]
+;
+  %A = getelementptr i32, i32* %I, i8 17
+  %B = getelementptr i32, i32* %A, i16 4
+  ret i32* %B
+}
+
+; Test that two getelementptr insts fold
+define i32* @test2({ i32 }* %I) {
+; CHECK-LABEL: @test2(
+; CHECK-NEXT:    [[B:%.*]] = getelementptr { i32 }, { i32 }* [[I:%.*]], i32 1, i32 0
+; CHECK-NEXT:    ret i32* [[B]]
+;
+  %A = getelementptr { i32 }, { i32 }* %I, i32 1
+  %B = getelementptr { i32 }, { i32 }* %A, i32 0, i32 0
+  ret i32* %B
+}
+
+define void @test3(i8 %B) {
+; This should be turned into a constexpr instead of being an instruction
+; CHECK-LABEL: @test3(
+; CHECK-NEXT:    store i8 [[B:%.*]], i8* getelementptr inbounds ([10 x i8], [10 x i8]* @Global, i32 0, i32 4), align 1
+; CHECK-NEXT:    ret void
+;
+  %A = getelementptr [10 x i8], [10 x i8]* @Global, i32 0, i32 4
+  store i8 %B, i8* %A
+  ret void
+}
+
+%as1_ptr_struct = type { i32 addrspace(1)* }
+%as2_ptr_struct = type { i32 addrspace(2)* }
+
+@global_as2 = addrspace(2) global i32 zeroinitializer
+@global_as1_as2_ptr = addrspace(1) global %as2_ptr_struct { i32 addrspace(2)* @global_as2 }
+
+; This should be turned into a constexpr instead of being an instruction
+define void @test_evaluate_gep_nested_as_ptrs(i32 addrspace(2)* %B) {
+; CHECK-LABEL: @test_evaluate_gep_nested_as_ptrs(
+; CHECK-NEXT:    store i32 addrspace(2)* [[B:%.*]], i32 addrspace(2)* addrspace(1)* getelementptr inbounds (%as2_ptr_struct, [[AS2_PTR_STRUCT:%.*]] addrspace(1)* @global_as1_as2_ptr, i32 0, i32 0), align 8
+; CHECK-NEXT:    ret void
+;
+  %A = getelementptr %as2_ptr_struct, %as2_ptr_struct addrspace(1)* @global_as1_as2_ptr, i32 0, i32 0
+  store i32 addrspace(2)* %B, i32 addrspace(2)* addrspace(1)* %A
+  ret void
+}
+
+@arst = addrspace(1) global [4 x i8 addrspace(2)*] zeroinitializer
+
+define void @test_evaluate_gep_as_ptrs_array(i8 addrspace(2)* %B) {
+; CHECK-LABEL: @test_evaluate_gep_as_ptrs_array(
+; CHECK-NEXT:    store i8 addrspace(2)* [[B:%.*]], i8 addrspace(2)* addrspace(1)* getelementptr inbounds ([4 x i8 addrspace(2)*], [4 x i8 addrspace(2)*] addrspace(1)* @arst, i32 0, i32 2), align 16
+; CHECK-NEXT:    ret void
+;
+
+  %A = getelementptr [4 x i8 addrspace(2)*], [4 x i8 addrspace(2)*] addrspace(1)* @arst, i16 0, i16 2
+  store i8 addrspace(2)* %B, i8 addrspace(2)* addrspace(1)* %A
+  ret void
+}
+
+define i32* @test4(i32* %I, i32 %C, i32 %D) {
+; CHECK-LABEL: @test4(
+; CHECK-NEXT:    [[A:%.*]] = getelementptr i32, i32* [[I:%.*]], i32 [[C:%.*]]
+; CHECK-NEXT:    [[B:%.*]] = getelementptr i32, i32* [[A]], i32 [[D:%.*]]
+; CHECK-NEXT:    ret i32* [[B]]
+;
+  %A = getelementptr i32, i32* %I, i32 %C
+  %B = getelementptr i32, i32* %A, i32 %D
+  ret i32* %B
+}
+
+
+define i1 @test5({ i32, i32 }* %x, { i32, i32 }* %y) {
+; CHECK-LABEL: @test5(
+; CHECK-NEXT:    [[TMP_4:%.*]] = icmp eq { i32, i32 }* [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[TMP_4]]
+;
+  %tmp.1 = getelementptr { i32, i32 }, { i32, i32 }* %x, i32 0, i32 1
+  %tmp.3 = getelementptr { i32, i32 }, { i32, i32 }* %y, i32 0, i32 1
+  ;; seteq x, y
+  %tmp.4 = icmp eq i32* %tmp.1, %tmp.3
+  ret i1 %tmp.4
+}
+
+%S = type { i32, [ 100 x i32] }
+
+define <2 x i1> @test6(<2 x i32> %X, <2 x %S*> %P) nounwind {
+; CHECK-LABEL: @test6(
+; CHECK-NEXT:    [[C:%.*]] = icmp eq <2 x i32> [[X:%.*]], <i32 1073741823, i32 1073741823>
+; CHECK-NEXT:    ret <2 x i1> [[C]]
+;
+  %A = getelementptr inbounds %S, <2 x %S*> %P, <2 x i32> zeroinitializer, <2 x i32> <i32 1, i32 1>, <2 x i32> %X
+  %B = getelementptr inbounds %S, <2 x %S*> %P, <2 x i32> <i32 0, i32 0>, <2 x i32> <i32 0, i32 0>
+  %C = icmp eq <2 x i32*> %A, %B
+  ret <2 x i1> %C
+}
+
+@G = external global [3 x i8]
+define i8* @test7(i16 %Idx) {
+; CHECK-LABEL: @test7(
+; CHECK-NEXT:    [[ZE_IDX:%.*]] = zext i16 [[IDX:%.*]] to i32
+; CHECK-NEXT:    [[TMP:%.*]] = getelementptr [3 x i8], [3 x i8]* @G, i32 0, i32 [[ZE_IDX]]
+; CHECK-NEXT:    ret i8* [[TMP]]
+;
+  %ZE_Idx = zext i16 %Idx to i32
+  %tmp = getelementptr i8, i8* getelementptr ([3 x i8], [3 x i8]* @G, i32 0, i32 0), i32 %ZE_Idx
+  ret i8* %tmp
+}
+
+
+; Test folding of constantexpr geps into normal geps.
+@Array = external global [40 x i32]
+define i32 *@test8(i32 %X) {
+; CHECK-LABEL: @test8(
+; CHECK-NEXT:    [[A:%.*]] = getelementptr [40 x i32], [40 x i32]* @Array, i32 0, i32 [[X:%.*]]
+; CHECK-NEXT:    ret i32* [[A]]
+;
+  %A = getelementptr i32, i32* getelementptr ([40 x i32], [40 x i32]* @Array, i32 0, i32 0), i32 %X
+  ret i32* %A
+}
+
+define i32 *@test9(i32 *%base, i8 %ind) {
+; CHECK-LABEL: @test9(
+; CHECK-NEXT:    [[TMP1:%.*]] = sext i8 [[IND:%.*]] to i32
+; CHECK-NEXT:    [[RES:%.*]] = getelementptr i32, i32* [[BASE:%.*]], i32 [[TMP1]]
+; CHECK-NEXT:    ret i32* [[RES]]
+;
+  %res = getelementptr i32, i32 *%base, i8 %ind
+  ret i32* %res
+}
+
+define i32 @test10() {
+; CHECK-LABEL: @test10(
+; CHECK-NEXT:    ret i32 8
+;
+  %A = getelementptr { i32, double }, { i32, double }* null, i32 0, i32 1
+  %B = ptrtoint double* %A to i32
+  ret i32 %B
+}