[ImplicitNullChecks] Work with implicit defs.
Summary:
This change generalizes the implicit null checks pass to work with
instructions that don't have any explicit register defs. This lets us
use X86's `cmp` against memory as faulting load instructions.
Reviewers: reames, JosephTremoulet
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11286
llvm-svn: 242703
diff --git a/llvm/test/CodeGen/X86/implicit-null-check.ll b/llvm/test/CodeGen/X86/implicit-null-check.ll
index fd7a902..8b905f5 100644
--- a/llvm/test/CodeGen/X86/implicit-null-check.ll
+++ b/llvm/test/CodeGen/X86/implicit-null-check.ll
@@ -101,6 +101,40 @@
ret i32 %t1
}
+define i32 @imp_null_check_via_mem_comparision(i32* %x, i32 %val) {
+; CHECK-LABEL: _imp_null_check_via_mem_comparision
+; CHECK: Ltmp9:
+; CHECK: cmpl %esi, 4(%rdi)
+; CHECK: jge LBB4_2
+; CHECK: movl $100, %eax
+; CHECK: retq
+; CHECK: Ltmp8:
+; CHECK: movl $42, %eax
+; CHECK: retq
+; CHECK: LBB4_2:
+; CHECK: movl $200, %eax
+; CHECK: retq
+
+ entry:
+ %c = icmp eq i32* %x, null
+ br i1 %c, label %is_null, label %not_null, !make.implicit !0
+
+ is_null:
+ ret i32 42
+
+ not_null:
+ %x.loc = getelementptr i32, i32* %x, i32 1
+ %t = load i32, i32* %x.loc
+ %m = icmp slt i32 %t, %val
+ br i1 %m, label %ret_100, label %ret_200
+
+ ret_100:
+ ret i32 100
+
+ ret_200:
+ ret i32 200
+}
+
!0 = !{}
; CHECK-LABEL: __LLVM_FaultMaps:
@@ -113,7 +147,7 @@
; CHECK-NEXT: .short 0
; # functions:
-; CHECK-NEXT: .long 4
+; CHECK-NEXT: .long 5
; FunctionAddr:
; CHECK-NEXT: .quad _imp_null_check_add_result
@@ -167,9 +201,22 @@
; Fault[0].HandlerOffset:
; CHECK-NEXT: .long Ltmp0-_imp_null_check_load
+; FunctionAddr:
+; CHECK-NEXT: .quad _imp_null_check_via_mem_comparision
+; NumFaultingPCs
+; CHECK-NEXT: .long 1
+; Reserved:
+; CHECK-NEXT: .long 0
+; Fault[0].Type:
+; CHECK-NEXT: .long 1
+; Fault[0].FaultOffset:
+; CHECK-NEXT: .long Ltmp9-_imp_null_check_via_mem_comparision
+; Fault[0].HandlerOffset:
+; CHECK-NEXT: .long Ltmp8-_imp_null_check_via_mem_comparision
+
; OBJDUMP: FaultMap table:
; OBJDUMP-NEXT: Version: 0x1
-; OBJDUMP-NEXT: NumFunctions: 4
+; OBJDUMP-NEXT: NumFunctions: 5
; OBJDUMP-NEXT: FunctionAddress: 0x000000, NumFaultingPCs: 1
; OBJDUMP-NEXT: Fault kind: FaultingLoad, faulting PC offset: 0, handling PC offset: 5
; OBJDUMP-NEXT: FunctionAddress: 0x000000, NumFaultingPCs: 1