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, 660 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SimplifyCFG/switch_create-custom-dl.ll b/llvm/test/Transforms/SimplifyCFG/switch_create-custom-dl.ll
new file mode 100644
index 00000000000..7dce54d75d6
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/switch_create-custom-dl.ll
@@ -0,0 +1,660 @@
+; RUN: opt -S -simplifycfg < %s | FileCheck %s
+target datalayout="p:40:64:64:32"
+
+declare void @foo1()
+
+declare void @foo2()
+
+define void @test1(i32 %V) {
+        %C1 = icmp eq i32 %V, 4         ; <i1> [#uses=1]
+        %C2 = icmp eq i32 %V, 17                ; <i1> [#uses=1]
+        %CN = or i1 %C1, %C2            ; <i1> [#uses=1]
+        br i1 %CN, label %T, label %F
+T:              ; preds = %0
+        call void @foo1( )
+        ret void
+F:              ; preds = %0
+        call void @foo2( )
+        ret void
+; CHECK-LABEL: @test1(
+; CHECK:  switch i32 %V, label %F [
+; CHECK:    i32 17, label %T
+; CHECK:    i32 4, label %T
+; CHECK:  ]
+}
+
+define void @test1_ptr(i32* %V) {
+        %C1 = icmp eq i32* %V, inttoptr (i32 4 to i32*)
+        %C2 = icmp eq i32* %V, inttoptr (i32 17 to i32*)
+        %CN = or i1 %C1, %C2            ; <i1> [#uses=1]
+        br i1 %CN, label %T, label %F
+T:              ; preds = %0
+        call void @foo1( )
+        ret void
+F:              ; preds = %0
+        call void @foo2( )
+        ret void
+; CHECK-LABEL: @test1_ptr(
+; DL:  %magicptr = ptrtoint i32* %V to i32
+; DL:  switch i32 %magicptr, label %F [
+; DL:    i32 17, label %T
+; DL:    i32 4, label %T
+; DL:  ]
+}
+
+define void @test1_ptr_as1(i32 addrspace(1)* %V) {
+        %C1 = icmp eq i32 addrspace(1)* %V, inttoptr (i32 4 to i32 addrspace(1)*)
+        %C2 = icmp eq i32 addrspace(1)* %V, inttoptr (i32 17 to i32 addrspace(1)*)
+        %CN = or i1 %C1, %C2            ; <i1> [#uses=1]
+        br i1 %CN, label %T, label %F
+T:              ; preds = %0
+        call void @foo1( )
+        ret void
+F:              ; preds = %0
+        call void @foo2( )
+        ret void
+; CHECK-LABEL: @test1_ptr_as1(
+; DL:  %magicptr = ptrtoint i32 addrspace(1)* %V to i16
+; DL:  switch i16 %magicptr, label %F [
+; DL:    i16 17, label %T
+; DL:    i16 4, label %T
+; DL:  ]
+}
+
+define void @test2(i32 %V) {
+        %C1 = icmp ne i32 %V, 4         ; <i1> [#uses=1]
+        %C2 = icmp ne i32 %V, 17                ; <i1> [#uses=1]
+        %CN = and i1 %C1, %C2           ; <i1> [#uses=1]
+        br i1 %CN, label %T, label %F
+T:              ; preds = %0
+        call void @foo1( )
+        ret void
+F:              ; preds = %0
+        call void @foo2( )
+        ret void
+; CHECK-LABEL: @test2(
+; CHECK:  switch i32 %V, label %T [
+; CHECK:    i32 17, label %F
+; CHECK:    i32 4, label %F
+; CHECK:  ]
+}
+
+define void @test3(i32 %V) {
+        %C1 = icmp eq i32 %V, 4         ; <i1> [#uses=1]
+        br i1 %C1, label %T, label %N
+N:              ; preds = %0
+        %C2 = icmp eq i32 %V, 17                ; <i1> [#uses=1]
+        br i1 %C2, label %T, label %F
+T:              ; preds = %N, %0
+        call void @foo1( )
+        ret void
+F:              ; preds = %N
+        call void @foo2( )
+        ret void
+
+; CHECK-LABEL: @test3(
+; CHECK: switch i32 %V, label %F [
+; CHECK:     i32 4, label %T
+; CHECK:     i32 17, label %T
+; CHECK:   ]
+}
+
+
+
+define i32 @test4(i8 zeroext %c) nounwind ssp noredzone {
+entry:
+  %cmp = icmp eq i8 %c, 62
+  br i1 %cmp, label %lor.end, label %lor.lhs.false
+
+lor.lhs.false:                                    ; preds = %entry
+  %cmp4 = icmp eq i8 %c, 34
+  br i1 %cmp4, label %lor.end, label %lor.rhs
+
+lor.rhs:                                          ; preds = %lor.lhs.false
+  %cmp8 = icmp eq i8 %c, 92
+  br label %lor.end
+
+lor.end:                                          ; preds = %lor.rhs, %lor.lhs.false, %entry
+  %0 = phi i1 [ true, %lor.lhs.false ], [ true, %entry ], [ %cmp8, %lor.rhs ]
+  %lor.ext = zext i1 %0 to i32
+  ret i32 %lor.ext
+
+; CHECK-LABEL: @test4(
+; CHECK:  switch i8 %c, label %lor.rhs [
+; CHECK:    i8 62, label %lor.end
+; CHECK:    i8 34, label %lor.end
+; CHECK:    i8 92, label %lor.end
+; CHECK:  ]
+}
+
+define i32 @test5(i8 zeroext %c) nounwind ssp noredzone {
+entry:
+  switch i8 %c, label %lor.rhs [
+    i8 62, label %lor.end
+    i8 34, label %lor.end
+    i8 92, label %lor.end
+  ]
+
+lor.rhs:                                          ; preds = %entry
+  %V = icmp eq i8 %c, 92
+  br label %lor.end
+
+lor.end:                                          ; preds = %entry, %entry, %entry, %lor.rhs
+  %0 = phi i1 [ true, %entry ], [ %V, %lor.rhs ], [ true, %entry ], [ true, %entry ]
+  %lor.ext = zext i1 %0 to i32
+  ret i32 %lor.ext
+; CHECK-LABEL: @test5(
+; CHECK:  switch i8 %c, label %lor.rhs [
+; CHECK:    i8 62, label %lor.end
+; CHECK:    i8 34, label %lor.end
+; CHECK:    i8 92, label %lor.end
+; CHECK:  ]
+}
+
+
+define i1 @test6({ i32, i32 }* %I) {
+entry:
+        %tmp.1.i = getelementptr { i32, i32 }, { i32, i32 }* %I, i64 0, i32 1         ; <i32*> [#uses=1]
+        %tmp.2.i = load i32, i32* %tmp.1.i           ; <i32> [#uses=6]
+        %tmp.2 = icmp eq i32 %tmp.2.i, 14               ; <i1> [#uses=1]
+        br i1 %tmp.2, label %shortcirc_done.4, label %shortcirc_next.0
+shortcirc_next.0:               ; preds = %entry
+        %tmp.6 = icmp eq i32 %tmp.2.i, 15               ; <i1> [#uses=1]
+        br i1 %tmp.6, label %shortcirc_done.4, label %shortcirc_next.1
+shortcirc_next.1:               ; preds = %shortcirc_next.0
+        %tmp.11 = icmp eq i32 %tmp.2.i, 16              ; <i1> [#uses=1]
+        br i1 %tmp.11, label %shortcirc_done.4, label %shortcirc_next.2
+shortcirc_next.2:               ; preds = %shortcirc_next.1
+        %tmp.16 = icmp eq i32 %tmp.2.i, 17              ; <i1> [#uses=1]
+        br i1 %tmp.16, label %shortcirc_done.4, label %shortcirc_next.3
+shortcirc_next.3:               ; preds = %shortcirc_next.2
+        %tmp.21 = icmp eq i32 %tmp.2.i, 18              ; <i1> [#uses=1]
+        br i1 %tmp.21, label %shortcirc_done.4, label %shortcirc_next.4
+shortcirc_next.4:               ; preds = %shortcirc_next.3
+        %tmp.26 = icmp eq i32 %tmp.2.i, 19              ; <i1> [#uses=1]
+        br label %UnifiedReturnBlock
+shortcirc_done.4:               ; preds = %shortcirc_next.3, %shortcirc_next.2, %shortcirc_next.1, %shortcirc_next.0, %entry
+        br label %UnifiedReturnBlock
+UnifiedReturnBlock:             ; preds = %shortcirc_done.4, %shortcirc_next.4
+        %UnifiedRetVal = phi i1 [ %tmp.26, %shortcirc_next.4 ], [ true, %shortcirc_done.4 ]             ; <i1> [#uses=1]
+        ret i1 %UnifiedRetVal
+
+; CHECK-LABEL: @test6(
+; CHECK: %tmp.2.i.off = add i32 %tmp.2.i, -14
+; CHECK: %switch = icmp ult i32 %tmp.2.i.off, 6
+}
+
+define void @test7(i8 zeroext %c, i32 %x) nounwind ssp noredzone {
+entry:
+  %cmp = icmp ult i32 %x, 32
+  %cmp4 = icmp eq i8 %c, 97
+  %or.cond = or i1 %cmp, %cmp4
+  %cmp9 = icmp eq i8 %c, 99
+  %or.cond11 = or i1 %or.cond, %cmp9
+  br i1 %or.cond11, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  tail call void @foo1() nounwind noredzone
+  ret void
+
+if.end:                                           ; preds = %entry
+  ret void
+
+; CHECK-LABEL: @test7(
+; CHECK:   %cmp = icmp ult i32 %x, 32
+; CHECK:   br i1 %cmp, label %if.then, label %switch.early.test
+; CHECK: switch.early.test:
+; CHECK:   switch i8 %c, label %if.end [
+; CHECK:     i8 99, label %if.then
+; CHECK:     i8 97, label %if.then
+; CHECK:   ]
+}
+
+define i32 @test8(i8 zeroext %c, i32 %x, i1 %C) nounwind ssp noredzone {
+entry:
+  br i1 %C, label %N, label %if.then
+N:
+  %cmp = icmp ult i32 %x, 32
+  %cmp4 = icmp eq i8 %c, 97
+  %or.cond = or i1 %cmp, %cmp4
+  %cmp9 = icmp eq i8 %c, 99
+  %or.cond11 = or i1 %or.cond, %cmp9
+  br i1 %or.cond11, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  %A = phi i32 [0, %entry], [42, %N]
+  tail call void @foo1() nounwind noredzone
+  ret i32 %A
+
+if.end:                                           ; preds = %entry
+  ret i32 0
+
+; CHECK-LABEL: @test8(
+; CHECK: switch.early.test:
+; CHECK:   switch i8 %c, label %if.end [
+; CHECK:     i8 99, label %if.then
+; CHECK:     i8 97, label %if.then
+; CHECK:   ]
+; CHECK:   %A = phi i32 [ 0, %entry ], [ 42, %switch.early.test ], [ 42, %N ], [ 42, %switch.early.test ]
+}
+
+;; This is "Example 7" from http://blog.regehr.org/archives/320
+define i32 @test9(i8 zeroext %c) nounwind ssp noredzone {
+entry:
+  %cmp = icmp ult i8 %c, 33
+  br i1 %cmp, label %lor.end, label %lor.lhs.false
+
+lor.lhs.false:                                    ; preds = %entry
+  %cmp4 = icmp eq i8 %c, 46
+  br i1 %cmp4, label %lor.end, label %lor.lhs.false6
+
+lor.lhs.false6:                                   ; preds = %lor.lhs.false
+  %cmp9 = icmp eq i8 %c, 44
+  br i1 %cmp9, label %lor.end, label %lor.lhs.false11
+
+lor.lhs.false11:                                  ; preds = %lor.lhs.false6
+  %cmp14 = icmp eq i8 %c, 58
+  br i1 %cmp14, label %lor.end, label %lor.lhs.false16
+
+lor.lhs.false16:                                  ; preds = %lor.lhs.false11
+  %cmp19 = icmp eq i8 %c, 59
+  br i1 %cmp19, label %lor.end, label %lor.lhs.false21
+
+lor.lhs.false21:                                  ; preds = %lor.lhs.false16
+  %cmp24 = icmp eq i8 %c, 60
+  br i1 %cmp24, label %lor.end, label %lor.lhs.false26
+
+lor.lhs.false26:                                  ; preds = %lor.lhs.false21
+  %cmp29 = icmp eq i8 %c, 62
+  br i1 %cmp29, label %lor.end, label %lor.lhs.false31
+
+lor.lhs.false31:                                  ; preds = %lor.lhs.false26
+  %cmp34 = icmp eq i8 %c, 34
+  br i1 %cmp34, label %lor.end, label %lor.lhs.false36
+
+lor.lhs.false36:                                  ; preds = %lor.lhs.false31
+  %cmp39 = icmp eq i8 %c, 92
+  br i1 %cmp39, label %lor.end, label %lor.rhs
+
+lor.rhs:                                          ; preds = %lor.lhs.false36
+  %cmp43 = icmp eq i8 %c, 39
+  br label %lor.end
+
+lor.end:                                          ; preds = %lor.rhs, %lor.lhs.false36, %lor.lhs.false31, %lor.lhs.false26, %lor.lhs.false21, %lor.lhs.false16, %lor.lhs.false11, %lor.lhs.false6, %lor.lhs.false, %entry
+  %0 = phi i1 [ true, %lor.lhs.false36 ], [ true, %lor.lhs.false31 ], [ true, %lor.lhs.false26 ], [ true, %lor.lhs.false21 ], [ true, %lor.lhs.false16 ], [ true, %lor.lhs.false11 ], [ true, %lor.lhs.false6 ], [ true, %lor.lhs.false ], [ true, %entry ], [ %cmp43, %lor.rhs ]
+  %conv46 = zext i1 %0 to i32
+  ret i32 %conv46
+
+; CHECK-LABEL: @test9(
+; CHECK:   %cmp = icmp ult i8 %c, 33
+; CHECK:   br i1 %cmp, label %lor.end, label %switch.early.test
+
+; CHECK: switch.early.test:
+; CHECK:   switch i8 %c, label %lor.rhs [
+; CHECK:     i8 92, label %lor.end
+; CHECK:     i8 62, label %lor.end
+; CHECK:     i8 60, label %lor.end
+; CHECK:     i8 59, label %lor.end
+; CHECK:     i8 58, label %lor.end
+; CHECK:     i8 46, label %lor.end
+; CHECK:     i8 44, label %lor.end
+; CHECK:     i8 34, label %lor.end
+; CHECK:     i8 39, label %lor.end
+; CHECK:   ]
+}
+
+define i32 @test10(i32 %mode, i1 %Cond) {
+  %A = icmp ne i32 %mode, 0
+  %B = icmp ne i32 %mode, 51
+  %C = and i1 %A, %B
+  %D = and i1 %C, %Cond
+  br i1 %D, label %T, label %F
+T:
+  ret i32 123
+F:
+  ret i32 324
+
+; CHECK-LABEL: @test10(
+; CHECK:  br i1 %Cond, label %switch.early.test, label %F
+; CHECK:switch.early.test:
+; CHECK:  switch i32 %mode, label %T [
+; CHECK:    i32 51, label %F
+; CHECK:    i32 0, label %F
+; CHECK:  ]
+}
+
+; PR8780
+define i32 @test11(i32 %bar) nounwind {
+entry:
+  %cmp = icmp eq i32 %bar, 4
+  %cmp2 = icmp eq i32 %bar, 35
+  %or.cond = or i1 %cmp, %cmp2
+  %cmp5 = icmp eq i32 %bar, 53
+  %or.cond1 = or i1 %or.cond, %cmp5
+  %cmp8 = icmp eq i32 %bar, 24
+  %or.cond2 = or i1 %or.cond1, %cmp8
+  %cmp11 = icmp eq i32 %bar, 23
+  %or.cond3 = or i1 %or.cond2, %cmp11
+  %cmp14 = icmp eq i32 %bar, 55
+  %or.cond4 = or i1 %or.cond3, %cmp14
+  %cmp17 = icmp eq i32 %bar, 12
+  %or.cond5 = or i1 %or.cond4, %cmp17
+  %cmp20 = icmp eq i32 %bar, 35
+  %or.cond6 = or i1 %or.cond5, %cmp20
+  br i1 %or.cond6, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  br label %return
+
+if.end:                                           ; preds = %entry
+  br label %return
+
+return:                                           ; preds = %if.end, %if.then
+  %retval.0 = phi i32 [ 1, %if.then ], [ 0, %if.end ]
+  ret i32 %retval.0
+
+; CHECK-LABEL: @test11(
+; CHECK: switch i32 %bar, label %if.end [
+; CHECK:   i32 55, label %return
+; CHECK:   i32 53, label %return
+; CHECK:   i32 35, label %return
+; CHECK:   i32 24, label %return
+; CHECK:   i32 23, label %return
+; CHECK:   i32 12, label %return
+; CHECK:   i32 4, label %return
+; CHECK: ]
+}
+
+define void @test12() nounwind {
+entry:
+  br label %bb49.us.us
+
+bb49.us.us:
+  %A = icmp eq i32 undef, undef
+  br i1 %A, label %bb55.us.us, label %malformed
+
+bb48.us.us:
+  %B = icmp ugt i32 undef, undef
+  br i1 %B, label %bb55.us.us, label %bb49.us.us
+
+bb55.us.us:
+  br label %bb48.us.us
+
+malformed:
+  ret void
+; CHECK-LABEL: @test12(
+
+}
+
+; test13 - handle switch formation with ult.
+define void @test13(i32 %x) nounwind ssp noredzone {
+entry:
+  %cmp = icmp ult i32 %x, 2
+  br i1 %cmp, label %if.then, label %lor.lhs.false3
+
+lor.lhs.false3:                                   ; preds = %lor.lhs.false
+  %cmp5 = icmp eq i32 %x, 3
+  br i1 %cmp5, label %if.then, label %lor.lhs.false6
+
+lor.lhs.false6:                                   ; preds = %lor.lhs.false3
+  %cmp8 = icmp eq i32 %x, 4
+  br i1 %cmp8, label %if.then, label %lor.lhs.false9
+
+lor.lhs.false9:                                   ; preds = %lor.lhs.false6
+  %cmp11 = icmp eq i32 %x, 6
+  br i1 %cmp11, label %if.then, label %if.end
+
+if.then:                                          ; preds = %lor.lhs.false9, %lor.lhs.false6, %lor.lhs.false3, %lor.lhs.false, %entry
+  call void @foo1() noredzone
+  br label %if.end
+
+if.end:                                           ; preds = %if.then, %lor.lhs.false9
+  ret void
+; CHECK-LABEL: @test13(
+; CHECK:  switch i32 %x, label %if.end [
+; CHECK:     i32 6, label %if.then
+; CHECK:     i32 4, label %if.then
+; CHECK:     i32 3, label %if.then
+; CHECK:     i32 1, label %if.then
+; CHECK:     i32 0, label %if.then
+; CHECK:   ]
+}
+
+; test14 - handle switch formation with ult.
+define void @test14(i32 %x) nounwind ssp noredzone {
+entry:
+  %cmp = icmp ugt i32 %x, 2
+  br i1 %cmp, label %lor.lhs.false3, label %if.then
+
+lor.lhs.false3:                                   ; preds = %lor.lhs.false
+  %cmp5 = icmp ne i32 %x, 3
+  br i1 %cmp5, label %lor.lhs.false6, label %if.then
+
+lor.lhs.false6:                                   ; preds = %lor.lhs.false3
+  %cmp8 = icmp ne i32 %x, 4
+  br i1 %cmp8, label %lor.lhs.false9, label %if.then
+
+lor.lhs.false9:                                   ; preds = %lor.lhs.false6
+  %cmp11 = icmp ne i32 %x, 6
+  br i1 %cmp11, label %if.end, label %if.then
+
+if.then:                                          ; preds = %lor.lhs.false9, %lor.lhs.false6, %lor.lhs.false3, %lor.lhs.false, %entry
+  call void @foo1() noredzone
+  br label %if.end
+
+if.end:                                           ; preds = %if.then, %lor.lhs.false9
+  ret void
+; CHECK-LABEL: @test14(
+; CHECK:  switch i32 %x, label %if.end [
+; CHECK:     i32 6, label %if.then
+; CHECK:     i32 4, label %if.then
+; CHECK:     i32 3, label %if.then
+; CHECK:     i32 1, label %if.then
+; CHECK:     i32 0, label %if.then
+; CHECK:   ]
+}
+
+; Don't crash on ginormous ranges.
+define void @test15(i128 %x) nounwind {
+  %cmp = icmp ugt i128 %x, 2
+  br i1 %cmp, label %if.end, label %lor.false
+
+lor.false:
+  %cmp2 = icmp ne i128 %x, 100000000000000000000
+  br i1 %cmp2, label %if.end, label %if.then
+
+if.then:
+  call void @foo1() noredzone
+  br label %if.end
+
+if.end:
+  ret void
+
+; CHECK-LABEL: @test15(
+; CHECK-NOT: switch
+; CHECK: ret void
+}
+
+; PR8675
+; rdar://5134905
+define zeroext i1 @test16(i32 %x) nounwind {
+entry:
+; CHECK-LABEL: @test16(
+; CHECK: %x.off = add i32 %x, -1
+; CHECK: %switch = icmp ult i32 %x.off, 3
+  %cmp.i = icmp eq i32 %x, 1
+  br i1 %cmp.i, label %lor.end, label %lor.lhs.false
+
+lor.lhs.false:
+  %cmp.i2 = icmp eq i32 %x, 2
+  br i1 %cmp.i2, label %lor.end, label %lor.rhs
+
+lor.rhs:
+  %cmp.i1 = icmp eq i32 %x, 3
+  br label %lor.end
+
+lor.end:
+  %0 = phi i1 [ true, %lor.lhs.false ], [ true, %entry ], [ %cmp.i1, %lor.rhs ]
+  ret i1 %0
+}
+
+; Check that we don't turn an icmp into a switch where it's not useful.
+define void @test17(i32 %x, i32 %y) {
+  %cmp = icmp ult i32 %x, 3
+  %switch = icmp ult i32 %y, 2
+  %or.cond775 = or i1 %cmp, %switch
+  br i1 %or.cond775, label %lor.lhs.false8, label %return
+
+lor.lhs.false8:
+  tail call void @foo1()
+  ret void
+
+return:
+  ret void
+
+; CHECK-LABEL: @test17(
+; CHECK-NOT: switch.early.test
+; CHECK-NOT: switch i32
+; CHECK: ret void
+}
+
+define void @test18(i32 %arg) {
+bb:
+  %tmp = and i32 %arg, -2
+  %tmp1 = icmp eq i32 %tmp, 8
+  %tmp2 = icmp eq i32 %arg, 10
+  %tmp3 = or i1 %tmp1, %tmp2
+  %tmp4 = icmp eq i32 %arg, 11
+  %tmp5 = or i1 %tmp3, %tmp4
+  %tmp6 = icmp eq i32 %arg, 12
+  %tmp7 = or i1 %tmp5, %tmp6
+  br i1 %tmp7, label %bb19, label %bb8
+
+bb8:                                              ; preds = %bb
+  %tmp9 = add i32 %arg, -13
+  %tmp10 = icmp ult i32 %tmp9, 2
+  %tmp11 = icmp eq i32 %arg, 16
+  %tmp12 = or i1 %tmp10, %tmp11
+  %tmp13 = icmp eq i32 %arg, 17
+  %tmp14 = or i1 %tmp12, %tmp13
+  %tmp15 = icmp eq i32 %arg, 18
+  %tmp16 = or i1 %tmp14, %tmp15
+  %tmp17 = icmp eq i32 %arg, 15
+  %tmp18 = or i1 %tmp16, %tmp17
+  br i1 %tmp18, label %bb19, label %bb20
+
+bb19:                                             ; preds = %bb8, %bb
+  tail call void @foo1()
+  br label %bb20
+
+bb20:                                             ; preds = %bb19, %bb8
+  ret void
+
+; CHECK-LABEL: @test18(
+; CHECK: %arg.off = add i32 %arg, -8
+; CHECK: icmp ult i32 %arg.off, 11
+}
+
+define void @PR26323(i1 %tobool23, i32 %tmp3) {
+entry:
+  %tobool5 = icmp ne i32 %tmp3, 0
+  %neg14 = and i32 %tmp3, -2
+  %cmp17 = icmp ne i32 %neg14, -1
+  %or.cond = and i1 %tobool5, %tobool23
+  %or.cond1 = and i1 %cmp17, %or.cond
+  br i1 %or.cond1, label %if.end29, label %if.then27
+
+if.then27:                                        ; preds = %entry
+  call void @foo1()
+  unreachable
+
+if.end29:                                         ; preds = %entry
+  ret void
+}
+
+; CHECK-LABEL: define void @PR26323(
+; CHECK:  %tobool5 = icmp ne i32 %tmp3, 0
+; CHECK:  %neg14 = and i32 %tmp3, -2
+; CHECK:  %cmp17 = icmp ne i32 %neg14, -1
+; CHECK:  %or.cond = and i1 %tobool5, %tobool23
+; CHECK:  %or.cond1 = and i1 %cmp17, %or.cond
+; CHECK:  br i1 %or.cond1, label %if.end29, label %if.then27
+
+; Form a switch when and'ing a negated power of two
+; CHECK-LABEL: define void @test19
+; CHECK: switch i32 %arg, label %else [
+; CHECK: i32 32, label %if
+; CHECK: i32 13, label %if
+; CHECK: i32 12, label %if
+define void @test19(i32 %arg) {
+  %and = and i32 %arg, -2
+  %cmp1 = icmp eq i32 %and, 12
+  %cmp2 = icmp eq i32 %arg, 32
+  %pred = or i1 %cmp1, %cmp2
+  br i1 %pred, label %if, label %else
+
+if:
+  call void @foo1()
+  ret void
+
+else:
+  ret void
+}
+
+; Since %cmp1 is always false, a switch is never formed
+; CHECK-LABEL: define void @test20
+; CHECK-NOT: switch
+; CHECK: ret void
+define void @test20(i32 %arg) {
+  %and = and i32 %arg, -2
+  %cmp1 = icmp eq i32 %and, 13
+  %cmp2 = icmp eq i32 %arg, 32
+  %pred = or i1 %cmp1, %cmp2
+  br i1 %pred, label %if, label %else
+
+if:
+  call void @foo1()
+  ret void
+
+else:
+  ret void
+}
+
+; Form a switch when or'ing a power of two
+; CHECK-LABEL: define void @test21
+; CHECK: i32 32, label %else
+; CHECK: i32 13, label %else
+; CHECK: i32 12, label %else
+define void @test21(i32 %arg) {
+  %and = or i32 %arg, 1
+  %cmp1 = icmp ne i32 %and, 13
+  %cmp2 = icmp ne i32 %arg, 32
+  %pred = and i1 %cmp1, %cmp2
+  br i1 %pred, label %if, label %else
+
+if:
+  call void @foo1()
+  ret void
+
+else:
+  ret void
+}
+
+; Since %cmp1 is always false, a switch is never formed
+; CHECK-LABEL: define void @test22
+; CHECK-NOT: switch
+; CHECK: ret void
+define void @test22(i32 %arg) {
+  %and = or i32 %arg, 1
+  %cmp1 = icmp ne i32 %and, 12
+  %cmp2 = icmp ne i32 %arg, 32
+  %pred = and i1 %cmp1, %cmp2
+  br i1 %pred, label %if, label %else
+
+if:
+  call void @foo1()
+  ret void
+
+else:
+  ret void
+}
\ No newline at end of file