For X86, change load/dec-or-inc/store into dec-or-inc, respectively.

This is a code change to add support for changing instruction sequences of the form:

  load
  inc/dec of 8/16/32/64 bits
  store

into the appropriate X86 inc/dec through memory instruction:

  inc[qlwb] / dec[qlwb]

The checks that were in X86DAGToDAGISel::Select(SDNode *Node)>>ISD::STORE have been extracted to isLoadIncOrDecStore and reworked to use the better
named wrappers for getOperand(unsigned) (e.g. getOffset()) and replaced Chain.getNode() with LoadNode.  The comments have also been expanded.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153635 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 179 insertions, 0 deletions

diff --git a/test/CodeGen/X86/rd-mod-wr-eflags.ll b/test/CodeGen/X86/rd-mod-wr-eflags.ll
new file mode 100644
index 0000000000..faca3d7bac
--- /dev/null
+++ b/test/CodeGen/X86/rd-mod-wr-eflags.ll
@@ -0,0 +1,179 @@
+; RUN: llc < %s -march=x86-64 | FileCheck %s
+
+%struct.obj = type { i64 }
+
+; CHECK: _Z7releaseP3obj
+define void @_Z7releaseP3obj(%struct.obj* nocapture %o) nounwind uwtable ssp {
+entry:
+; CHECK: decq	(%{{rdi|rcx}})
+; CHECK-NEXT: je
+  %refcnt = getelementptr inbounds %struct.obj* %o, i64 0, i32 0
+  %0 = load i64* %refcnt, align 8, !tbaa !0
+  %dec = add i64 %0, -1
+  store i64 %dec, i64* %refcnt, align 8, !tbaa !0
+  %tobool = icmp eq i64 %dec, 0
+  br i1 %tobool, label %if.end, label %return
+
+if.end:                                           ; preds = %entry
+  %1 = bitcast %struct.obj* %o to i8*
+  tail call void @free(i8* %1)
+  br label %return
+
+return:                                           ; preds = %entry, %if.end
+  ret void
+}
+
+@c = common global i64 0, align 8
+@a = common global i32 0, align 4
+@.str = private unnamed_addr constant [5 x i8] c"%ld\0A\00", align 1
+@b = common global i32 0, align 4
+
+; CHECK: test
+define i32 @test() nounwind uwtable ssp {
+entry:
+; CHECK: decq
+; CHECK-NOT: decq
+%0 = load i64* @c, align 8, !tbaa !0
+%dec.i = add nsw i64 %0, -1
+store i64 %dec.i, i64* @c, align 8, !tbaa !0
+%tobool.i = icmp ne i64 %dec.i, 0
+%lor.ext.i = zext i1 %tobool.i to i32
+store i32 %lor.ext.i, i32* @a, align 4, !tbaa !3
+%call = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([5 x i8]* @.str, i64 0, i64 0), i64 %dec.i) nounwind
+ret i32 0
+}
+
+; CHECK: test2
+define i32 @test2() nounwind uwtable ssp {
+entry:
+; CHECK-NOT: decq ({{.*}})
+%0 = load i64* @c, align 8, !tbaa !0
+%dec.i = add nsw i64 %0, -1
+store i64 %dec.i, i64* @c, align 8, !tbaa !0
+%tobool.i = icmp ne i64 %0, 0
+%lor.ext.i = zext i1 %tobool.i to i32
+store i32 %lor.ext.i, i32* @a, align 4, !tbaa !3
+%call = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([5 x i8]* @.str, i64 0, i64 0), i64 %dec.i) nounwind
+ret i32 0
+}
+
+declare i32 @printf(i8* nocapture, ...) nounwind
+
+declare void @free(i8* nocapture) nounwind
+
+!0 = metadata !{metadata !"long", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA", null}
+!3 = metadata !{metadata !"int", metadata !1}
+
+%struct.obj2 = type { i64, i32, i16, i8 }
+
+declare void @other(%struct.obj2* ) nounwind;
+
+; CHECK: example_dec
+define void @example_dec(%struct.obj2* %o) nounwind uwtable ssp {
+; 64 bit dec
+entry:
+  %s64 = getelementptr inbounds %struct.obj2* %o, i64 0, i32 0
+; CHECK-NOT: load 
+  %0 = load i64* %s64, align 8
+; CHECK: decq ({{.*}})
+  %dec = add i64 %0, -1
+  store i64 %dec, i64* %s64, align 8
+  %tobool = icmp eq i64 %dec, 0
+  br i1 %tobool, label %if.end, label %return
+
+; 32 bit dec
+if.end:
+  %s32 = getelementptr inbounds %struct.obj2* %o, i64 0, i32 1
+; CHECK-NOT: load 
+  %1 = load i32* %s32, align 4
+; CHECK: decl {{[0-9][0-9]*}}({{.*}})
+  %dec1 = add i32 %1, -1
+  store i32 %dec1, i32* %s32, align 4
+  %tobool2 = icmp eq i32 %dec1, 0
+  br i1 %tobool2, label %if.end1, label %return
+
+; 16 bit dec
+if.end1:
+  %s16 = getelementptr inbounds %struct.obj2* %o, i64 0, i32 2
+; CHECK-NOT: load 
+  %2 = load i16* %s16, align 2
+; CHECK: decw {{[0-9][0-9]*}}({{.*}})
+  %dec2 = add i16 %2, -1
+  store i16 %dec2, i16* %s16, align 2
+  %tobool3 = icmp eq i16 %dec2, 0
+  br i1 %tobool3, label %if.end2, label %return
+
+; 8 bit dec
+if.end2:
+  %s8 = getelementptr inbounds %struct.obj2* %o, i64 0, i32 3
+; CHECK-NOT: load 
+  %3 = load i8* %s8
+; CHECK: decb {{[0-9][0-9]*}}({{.*}})
+  %dec3 = add i8 %3, -1
+  store i8 %dec3, i8* %s8
+  %tobool4 = icmp eq i8 %dec3, 0
+  br i1 %tobool4, label %if.end4, label %return
+
+if.end4:
+  tail call void @other(%struct.obj2* %o) nounwind
+  br label %return
+
+return:                                           ; preds = %if.end4, %if.end, %entry                                                                                                                                                                               
+  ret void
+}
+
+; CHECK: example_inc
+define void @example_inc(%struct.obj2* %o) nounwind uwtable ssp {
+; 64 bit inc
+entry:
+  %s64 = getelementptr inbounds %struct.obj2* %o, i64 0, i32 0
+; CHECK-NOT: load 
+  %0 = load i64* %s64, align 8
+; CHECK: incq ({{.*}})
+  %inc = add i64 %0, 1
+  store i64 %inc, i64* %s64, align 8
+  %tobool = icmp eq i64 %inc, 0
+  br i1 %tobool, label %if.end, label %return
+
+; 32 bit inc
+if.end:
+  %s32 = getelementptr inbounds %struct.obj2* %o, i64 0, i32 1
+; CHECK-NOT: load 
+  %1 = load i32* %s32, align 4
+; CHECK: incl {{[0-9][0-9]*}}({{.*}})
+  %inc1 = add i32 %1, 1
+  store i32 %inc1, i32* %s32, align 4
+  %tobool2 = icmp eq i32 %inc1, 0
+  br i1 %tobool2, label %if.end1, label %return
+
+; 16 bit inc
+if.end1:
+  %s16 = getelementptr inbounds %struct.obj2* %o, i64 0, i32 2
+; CHECK-NOT: load 
+  %2 = load i16* %s16, align 2
+; CHECK: incw {{[0-9][0-9]*}}({{.*}})
+  %inc2 = add i16 %2, 1
+  store i16 %inc2, i16* %s16, align 2
+  %tobool3 = icmp eq i16 %inc2, 0
+  br i1 %tobool3, label %if.end2, label %return
+
+; 8 bit inc
+if.end2:
+  %s8 = getelementptr inbounds %struct.obj2* %o, i64 0, i32 3
+; CHECK-NOT: load 
+  %3 = load i8* %s8
+; CHECK: incb {{[0-9][0-9]*}}({{.*}})
+  %inc3 = add i8 %3, 1
+  store i8 %inc3, i8* %s8
+  %tobool4 = icmp eq i8 %inc3, 0
+  br i1 %tobool4, label %if.end4, label %return
+
+if.end4:
+  tail call void @other(%struct.obj2* %o) nounwind
+  br label %return
+
+return:
+  ret void
+}