[ISEL][BitTestBlock] pre-commit test for D109103

Upload a test that shows ISEL taking a SwitchInst that has an
unreachable BB for a default target being lowered to an unconditional
jump off the end of a function.

Link: https://bugs.llvm.org/show_bug.cgi?id=50080
Link: ClangBuiltLinux/linux#679
Link: ClangBuiltLinux/linux#1440

Reviewed By: craig.topper, hans

Differential Revision: https://reviews.llvm.org/D109106

Author: nickdesaulniers

llvm/test/CodeGen/X86/SwitchLowering.ll

@@ -62,3 +62,49 @@ bb7:            ; preds = %bb, %bb
 
 declare void @foo(i8)
 
+define i32 @baz(i32 %0) {
+; FIXME: Get rid of this conditional jump and bit test in .LBB1_1.
+; FIXME: .LBB1_4 should not have .LBB1_1 as a predecessor, or be past the end
+; FIXME: of the function.
+; CHECK-LABEL: baz:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    xorl %eax, %eax
+; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; CHECK-NEXT:    movl $13056, %edx # imm = 0x3300
+; CHECK-NEXT:    btl %ecx, %edx
+; CHECK-NEXT:    jae .LBB1_1
+; CHECK-NEXT:  # %bb.3: # %return
+; CHECK-NEXT:    retl
+; CHECK-NEXT:  .LBB1_1:
+; CHECK-NEXT:    movl $48, %eax
+; CHECK-NEXT:    btl %ecx, %eax
+; CHECK-NEXT:    jae .LBB1_4
+; CHECK-NEXT:  # %bb.2: # %sw.epilog8
+; CHECK-NEXT:    movl $1, %eax
+; CHECK-NEXT:    retl
+; CHECK-NEXT:  .LBB1_4: # %if.then.unreachabledefault
+  switch i32 %0, label %if.then.unreachabledefault [
+    i32 4, label %sw.epilog8
+    i32 5, label %sw.epilog8
+    i32 8, label %sw.bb2
+    i32 9, label %sw.bb2
+    i32 12, label %sw.bb4
+    i32 13, label %sw.bb4
+  ]
+
+sw.bb2:
+  br label %return
+
+sw.bb4:
+  br label %return
+
+sw.epilog8:
+  br label %return
+
+if.then.unreachabledefault:
+  unreachable
+
+return:
+  %retval.0 = phi i32 [ 1, %sw.epilog8 ], [ 0, %sw.bb2 ], [ 0, %sw.bb4 ]
+  ret i32 %retval.0
+}

llvm/test/CodeGen/X86/switch-bit-test-unreachable-default.ll

@@ -0,0 +1,117 @@
+; RUN: llc -mtriple=x86_64-- -global-isel=0 -print-after=finalize-isel \
+; RUN:   -stop-after=finalize-isel %s -o /dev/null 2>&1 | \
+; RUN:   FileCheck %s --check-prefix=CHECK-SDISEL
+; RUN: llc -mtriple=x86_64-- -global-isel=1 -print-after=finalize-isel \
+; RUN:   -stop-after=finalize-isel %s -o /dev/null 2>&1 | \
+; RUN:   FileCheck %s --check-prefix=CHECK-GISEL
+
+; PR50080
+define i32 @baz(i32 %0) {
+; FIXME: Get rid of this conditional jump and bit test in bb.5.
+; FIXME: bb.2 should not have bb.5 as a predecessor.
+; CHECK-SDISEL: bb.0 (%ir-block.1):
+; CHECK-SDISEL:   successors: %bb.4(0x80000000); %bb.4(100.00%)
+; CHECK-SDISEL:   liveins: $edi
+; CHECK-SDISEL:   %1:gr32 = COPY $edi
+; CHECK-SDISEL:   %2:gr32 = MOV32r0 implicit-def dead $eflags
+; CHECK-SDISEL:   %3:gr32 = COPY %1:gr32
+; CHECK-SDISEL: bb.4 (%ir-block.1):
+; CHECK-SDISEL: ; predecessors: %bb.0
+; CHECK-SDISEL:   successors: %bb.3(0x55555555), %bb.5(0x2aaaaaab); %bb.3(66.67%), %bb.5(33.33%)
+; CHECK-SDISEL:   %4:gr32 = MOV32ri 13056
+; CHECK-SDISEL:   BT32rr killed %4:gr32, %3:gr32, implicit-def $eflags
+; CHECK-SDISEL:   JCC_1 %bb.3, 2, implicit $eflags
+; CHECK-SDISEL: bb.5 (%ir-block.1):
+; CHECK-SDISEL: ; predecessors: %bb.4
+; CHECK-SDISEL:   successors: %bb.1(0x80000000), %bb.2(0x00000000); %bb.1(100.00%), %bb.2(0.00%)
+; CHECK-SDISEL:   %5:gr32 = MOV32ri 48
+; CHECK-SDISEL:   BT32rr killed %5:gr32, %3:gr32, implicit-def $eflags
+; CHECK-SDISEL:   JCC_1 %bb.1, 2, implicit $eflags
+; CHECK-SDISEL:   JMP_1 %bb.2
+; CHECK-SDISEL: bb.1.sw.epilog8:
+; CHECK-SDISEL: ; predecessors: %bb.5
+; CHECK-SDISEL:   successors: %bb.3(0x80000000); %bb.3(100.00%)
+; CHECK-SDISEL:   %6:gr32 = MOV32ri 1
+; CHECK-SDISEL:   JMP_1 %bb.3
+; CHECK-SDISEL: bb.2.if.then.unreachabledefault:
+; CHECK-SDISEL: ; predecessors: %bb.5
+; CHECK-SDISEL: bb.3.return:
+; CHECK-SDISEL: ; predecessors: %bb.4, %bb.1
+; CHECK-SDISEL:   %0:gr32 = PHI %2:gr32, %bb.4, %6:gr32, %bb.1
+; CHECK-SDISEL:   $eax = COPY %0:gr32
+; CHECK-SDISEL:   RET 0, $eax
+
+
+; FIXME: Get rid of this conditional jump and bit test in bb.6.
+; FIXME: bb.3 should not have bb.6 as a predecessor.
+; CHECK-GISEL: bb.1 (%ir-block.1):
+; CHECK-GISEL:   successors: %bb.5(0x80000000); %bb.5(100.00%)
+; CHECK-GISEL:   liveins: $edi
+; CHECK-GISEL:   %0:gr32 = COPY $edi
+; CHECK-GISEL:   %16:gr32 = MOV32ri 1
+; CHECK-GISEL:   %17:gr32 = MOV32r0 implicit-def $eflags
+; CHECK-GISEL:   %2:gr32 = SUB32ri8 %0:gr32(tied-def 0), 0, implicit-def $eflags
+; CHECK-GISEL: bb.5 (%ir-block.1):
+; CHECK-GISEL: ; predecessors: %bb.1
+; CHECK-GISEL:   successors: %bb.4(0x55555555), %bb.6(0x2aaaaaab); %bb.4(66.67%), %bb.6(33.33%)
+; CHECK-GISEL:   %3:gr32 = MOV32ri 1
+; CHECK-GISEL:   %21:gr8 = COPY %2.sub_8bit:gr32
+; CHECK-GISEL:   $cl = COPY %21:gr8
+; CHECK-GISEL:   %4:gr32 = SHL32rCL %3:gr32(tied-def 0), implicit-def $eflags, implicit $cl
+; CHECK-GISEL:   %6:gr32 = AND32ri %4:gr32(tied-def 0), 13056, implicit-def $eflags
+; CHECK-GISEL:   %7:gr32 = MOV32r0 implicit-def $eflags
+; CHECK-GISEL:   CMP32rr %6:gr32, %7:gr32, implicit-def $eflags
+; CHECK-GISEL:   %20:gr8 = SETCCr 5, implicit $eflags
+; CHECK-GISEL:   TEST8ri %20:gr8, 1, implicit-def $eflags
+; CHECK-GISEL:   JCC_1 %bb.4, 5, implicit $eflags
+; CHECK-GISEL: bb.6 (%ir-block.1):
+; CHECK-GISEL: ; predecessors: %bb.5
+; CHECK-GISEL:   successors: %bb.2(0x80000000), %bb.3(0x00000000); %bb.2(100.00%), %bb.3(0.00%)
+; CHECK-GISEL:   %9:gr32 = MOV32ri 1
+; CHECK-GISEL:   %19:gr8 = COPY %2.sub_8bit:gr32
+; CHECK-GISEL:   $cl = COPY %19:gr8
+; CHECK-GISEL:   %10:gr32 = SHL32rCL %9:gr32(tied-def 0), implicit-def $eflags, implicit $cl
+; CHECK-GISEL:   %12:gr32 = AND32ri8 %10:gr32(tied-def 0), 48, implicit-def $eflags
+; CHECK-GISEL:   %13:gr32 = MOV32r0 implicit-def $eflags
+; CHECK-GISEL:   CMP32rr %12:gr32, %13:gr32, implicit-def $eflags
+; CHECK-GISEL:   %18:gr8 = SETCCr 5, implicit $eflags
+; CHECK-GISEL:   TEST8ri %18:gr8, 1, implicit-def $eflags
+; CHECK-GISEL:   JCC_1 %bb.2, 5, implicit $eflags
+; CHECK-GISEL:   JMP_1 %bb.3
+; CHECK-GISEL: bb.2.sw.epilog8:
+; CHECK-GISEL: ; predecessors: %bb.6
+; CHECK-GISEL:   successors: %bb.4(0x80000000); %bb.4(100.00%)
+; CHECK-GISEL:   JMP_1 %bb.4
+; CHECK-GISEL: bb.3.if.then.unreachabledefault:
+; CHECK-GISEL: ; predecessors: %bb.6
+; CHECK-GISEL: bb.4.return:
+; CHECK-GISEL: ; predecessors: %bb.5, %bb.2
+; CHECK-GISEL:   %15:gr32 = PHI %16:gr32, %bb.2, %17:gr32, %bb.5
+; CHECK-GISEL:   $eax = COPY %15:gr32
+; CHECK-GISEL:   RET 0, implicit $eax
+
+  switch i32 %0, label %if.then.unreachabledefault [
+    i32 4, label %sw.epilog8
+    i32 5, label %sw.epilog8
+    i32 8, label %sw.bb2
+    i32 9, label %sw.bb2
+    i32 12, label %sw.bb4
+    i32 13, label %sw.bb4
+  ]
+
+sw.bb2:
+  br label %return
+
+sw.bb4:
+  br label %return
+
+sw.epilog8:
+  br label %return
+
+if.then.unreachabledefault:
+  unreachable
+
+return:
+  %retval.0 = phi i32 [ 1, %sw.epilog8 ], [ 0, %sw.bb2 ], [ 0, %sw.bb4 ]
+  ret i32 %retval.0
+}