2 files changed, 224 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/select-implied.ll b/llvm/test/Transforms/InstCombine/select-implied.ll
index 2100e3eae00..6b2ec7ffce7 100644
--- a/llvm/test/Transforms/InstCombine/select-implied.ll
+++ b/llvm/test/Transforms/InstCombine/select-implied.ll
@@ -121,3 +121,44 @@ end:
 
 declare void @foo(i32)
 declare i32 @bar(i32)
+
+; CHECK-LABEL: @test_and
+; CHECK: tpath:
+; CHECK-NOT: select
+; CHECK: ret i32 313
+define i32 @test_and(i32 %a, i32 %b) {
+entry:
+  %cmp1 = icmp ne i32 %a, 0
+  %cmp2 = icmp ne i32 %b, 0
+  %and = and i1 %cmp1, %cmp2
+  br i1 %and, label %tpath, label %end
+
+tpath:
+  %cmp3 = icmp eq i32 %a, 0 ;; <-- implied false
+  %c = select i1 %cmp3, i32 0, i32 313
+  ret i32 %c
+
+end:
+  ret i32 0
+}
+
+; cmp1 and cmp2 are false on the 'fpath' path and thus cmp3 is true.
+; CHECK-LABEL: @test_or1
+; CHECK: fpath:
+; CHECK-NOT: select
+; CHECK: ret i32 37
+define i32 @test_or1(i32 %a, i32 %b) {
+entry:
+  %cmp1 = icmp eq i32 %a, 0
+  %cmp2 = icmp eq i32 %b, 0
+  %or = or i1 %cmp1, %cmp2
+  br i1 %or, label %end, label %fpath
+
+fpath:
+  %cmp3 = icmp ne i32 %a, 0  ;; <-- implied true
+  %c = select i1 %cmp3, i32 37, i32 0
+  ret i32 %c
+
+end:
+  ret i32 0
+}
diff --git a/llvm/test/Transforms/SimplifyCFG/implied-and-or.ll b/llvm/test/Transforms/SimplifyCFG/implied-and-or.ll
new file mode 100644
index 00000000000..e615f302fee
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/implied-and-or.ll
@@ -0,0 +1,183 @@
+; RUN: opt %s -S -simplifycfg | FileCheck %s
+
+declare void @foo()
+declare void @bar()
+
+
+; CHECK-LABEL: @test_and1
+; CHECK: taken:
+; CHECK-NOT: cmp3
+; CHECK: call void @bar()
+; CHECK-NEXT: call void @foo()
+; CHECK: ret
+define void @test_and1(i32 %a, i32 %b) {
+entry:
+  %cmp1 = icmp eq i32 %a, 0
+  %cmp2 = icmp eq i32 %b, 0
+  %and = and i1 %cmp1, %cmp2
+  br i1 %and, label %taken, label %end
+
+taken:
+  call void @bar()
+  %cmp3 = icmp eq i32 %a, 0  ;; <-- implied true
+  br i1 %cmp3, label %if.then, label %end
+
+if.then:
+  call void @foo()
+  br label %end
+
+end:
+  ret void
+}
+
+; We can't infer anything if the result of the 'and' is false
+; CHECK-LABEL: @test_and2
+; CHECK: taken:
+; CHECK:   call void @bar()
+; CHECK:   %cmp3
+; CHECK:   br i1 %cmp3
+; CHECK: if.then:
+; CHECK:   call void @foo()
+; CHECK: ret
+define void @test_and2(i32 %a, i32 %b) {
+entry:
+  %cmp1 = icmp eq i32 %a, 0
+  %cmp2 = icmp eq i32 %b, 0
+  %and = and i1 %cmp1, %cmp2
+  br i1 %and, label %end, label %taken
+
+taken:
+  call void @bar()
+  %cmp3 = icmp eq i32 %a, 0
+  br i1 %cmp3, label %if.then, label %end
+
+if.then:
+  call void @foo()
+  br label %end
+
+end:
+  ret void
+}
+
+; CHECK-LABEL: @test_or1
+; CHECK: taken:
+; CHECK-NOT: cmp3
+; CHECK: call void @bar()
+; CHECK-NEXT: call void @foo()
+; CHECK: ret
+define void @test_or1(i32 %a, i32 %b) {
+entry:
+  %cmp1 = icmp eq i32 %a, 0
+  %cmp2 = icmp eq i32 %b, 0
+  %or = or i1 %cmp1, %cmp2
+  br i1 %or, label %end, label %taken
+
+taken:
+  call void @bar()
+  %cmp3 = icmp ne i32 %a, 0   ;; <-- implied true
+  br i1 %cmp3, label %if.then, label %end
+
+if.then:
+  call void @foo()
+  br label %end
+
+end:
+  ret void
+}
+
+; We can't infer anything if the result of the 'or' is true
+; CHECK-LABEL: @test_or2
+; CHECK:   call void @bar()
+; CHECK:   %cmp3
+; CHECK:   br i1 %cmp3
+; CHECK: if.then:
+; CHECK:   call void @foo()
+; CHECK: ret
+define void @test_or2(i32 %a, i32 %b) {
+entry:
+  %cmp1 = icmp eq i32 %a, 0
+  %cmp2 = icmp eq i32 %b, 0
+  %or = or i1 %cmp1, %cmp2
+  br i1 %or, label %taken, label %end
+
+taken:
+  call void @bar()
+  %cmp3 = icmp eq i32 %a, 0
+  br i1 %cmp3, label %if.then, label %end
+
+if.then:
+  call void @foo()
+  br label %end
+
+end:
+  ret void
+}
+
+; We can recurse a tree of 'and' or 'or's.
+; CHECK-LABEL: @test_and_recurse1
+; CHECK: taken:
+; CHECK-NEXT:  call void @bar()
+; CHECK-NEXT:  call void @foo()
+; CHECK-NEXT:  br label %end
+; CHECK: ret
+define void @test_and_recurse1(i32 %a, i32 %b, i32 %c) {
+entry:
+  %cmpa = icmp eq i32 %a, 0
+  %cmpb = icmp eq i32 %b, 0
+  %cmpc = icmp eq i32 %c, 0
+  %and1 = and i1 %cmpa, %cmpb
+  %and2 = and i1 %and1, %cmpc
+  br i1 %and2, label %taken, label %end
+
+taken:
+  call void @bar()
+  %cmp3 = icmp eq i32 %a, 0
+  br i1 %cmp3, label %if.then, label %end
+
+if.then:
+  call void @foo()
+  br label %end
+
+end:
+  ret void
+}
+
+; Check to make sure we don't recurse too deep.
+; CHECK-LABEL: @test_and_recurse2
+; CHECK: taken:
+; CHECK-NEXT:  call void @bar()
+; CHECK-NEXT:  %cmp3 = icmp eq i32 %a, 0
+; CHECK-NEXT:  br i1 %cmp3, label %if.then, label %end
+; CHECK: ret
+define void @test_and_recurse2(i32 %a, i32 %b, i32 %c, i32 %d, i32 %e, i32 %f,
+                               i32 %g, i32 %h) {
+entry:
+  %cmpa = icmp eq i32 %a, 0
+  %cmpb = icmp eq i32 %b, 0
+  %cmpc = icmp eq i32 %c, 0
+  %cmpd = icmp eq i32 %d, 0
+  %cmpe = icmp eq i32 %e, 0
+  %cmpf = icmp eq i32 %f, 0
+  %cmpg = icmp eq i32 %g, 0
+  %cmph = icmp eq i32 %h, 0
+  %and1 = and i1 %cmpa, %cmpb
+  %and2 = and i1 %and1, %cmpc
+  %and3 = and i1 %and2, %cmpd
+  %and4 = and i1 %and3, %cmpe
+  %and5 = and i1 %and4, %cmpf
+  %and6 = and i1 %and5, %cmpg
+  %and7 = and i1 %and6, %cmph
+  br i1 %and7, label %taken, label %end
+
+taken:
+  call void @bar()
+  %cmp3 = icmp eq i32 %a, 0 ; <-- can be implied true
+  br i1 %cmp3, label %if.then, label %end
+
+if.then:
+  call void @foo()
+  br label %end
+
+end:
+  ret void
+}