[SelectionDAG] Remove debug locations from ConstantSD(FP)Nodes

This removes debug locations from ConstantSDNode and ConstantSDFPNode.

When this kind of node is materialized we no longer create a line table
entry which jumps back to the constant's first point of use. This makes
single-stepping behavior smoother, and it matches the model used by IR,
where Constants have no locations. See this thread for more context:

  http://lists.llvm.org/pipermail/llvm-dev/2018-June/124164.html

I'd like to handle constant BuildVectorSDNodes and to try to eliminate
passing SDLocs to SelectionDAG::getConstant*() in follow-up commits.

Differential Revision: https://reviews.llvm.org/D48468

llvm-svn: 335497

llvm/include/llvm/CodeGen/SelectionDAGNodes.h

@@ -1498,9 +1498,8 @@ class ConstantSDNode : public SDNode {
 
   const ConstantInt *Value;
 
-  ConstantSDNode(bool isTarget, bool isOpaque, const ConstantInt *val,
-                 const DebugLoc &DL, EVT VT)
-      : SDNode(isTarget ? ISD::TargetConstant : ISD::Constant, 0, DL,
+  ConstantSDNode(bool isTarget, bool isOpaque, const ConstantInt *val, EVT VT)
+      : SDNode(isTarget ? ISD::TargetConstant : ISD::Constant, 0, DebugLoc(),
                getSDVTList(VT)),
         Value(val) {
     ConstantSDNodeBits.IsOpaque = isOpaque;
@@ -1536,10 +1535,9 @@ class ConstantFPSDNode : public SDNode {
 
   const ConstantFP *Value;
 
-  ConstantFPSDNode(bool isTarget, const ConstantFP *val, const DebugLoc &DL,
-                   EVT VT)
-      : SDNode(isTarget ? ISD::TargetConstantFP : ISD::ConstantFP, 0, DL,
-               getSDVTList(VT)),
+  ConstantFPSDNode(bool isTarget, const ConstantFP *val, EVT VT)
+      : SDNode(isTarget ? ISD::TargetConstantFP : ISD::ConstantFP, 0,
+               DebugLoc(), getSDVTList(VT)),
         Value(val) {}
 
 public:

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

@@ -1243,7 +1243,7 @@ SDValue SelectionDAG::getConstant(const ConstantInt &Val, const SDLoc &DL,
       return SDValue(N, 0);
 
   if (!N) {
-    N = newSDNode<ConstantSDNode>(isT, isO, Elt, DL.getDebugLoc(), EltVT);
+    N = newSDNode<ConstantSDNode>(isT, isO, Elt, EltVT);
     CSEMap.InsertNode(N, IP);
     InsertNode(N);
     NewSDValueDbgMsg(SDValue(N, 0), "Creating constant: ", this);
@@ -1286,7 +1286,7 @@ SDValue SelectionDAG::getConstantFP(const ConstantFP &V, const SDLoc &DL,
       return SDValue(N, 0);
 
   if (!N) {
-    N = newSDNode<ConstantFPSDNode>(isTarget, &V, DL.getDebugLoc(), EltVT);
+    N = newSDNode<ConstantFPSDNode>(isTarget, &V, EltVT);
     CSEMap.InsertNode(N, IP);
     InsertNode(N);
   }

llvm/test/CodeGen/AArch64/machine-outliner-remarks.ll

@@ -1,18 +1,17 @@
 ; RUN: llc %s -enable-machine-outliner -mtriple=aarch64-unknown-unknown -pass-remarks=machine-outliner -pass-remarks-missed=machine-outliner -o /dev/null 2>&1 | FileCheck %s
-; CHECK: machine-outliner-remarks.ll:5:9:
+; CHECK: <unknown>:0:0:
 ; CHECK-SAME: Did not outline 2 instructions from 2 locations.
 ; CHECK-SAME: Bytes from outlining all occurrences (36) >=
 ; CHECK-SAME: Unoutlined instruction bytes (16)
-; CHECK-SAME: (Also found at: machine-outliner-remarks.ll:13:9)
+; CHECK-SAME: (Also found at: <UNKNOWN LOCATION>)
 ; CHECK: remark: <unknown>:0:0: Saved 20 bytes by outlining 12 instructions
-; CHECK-SAME: from 2 locations. (Found at: machine-outliner-remarks.ll:36:1,
-; CHECK-SAME: machine-outliner-remarks.ll:27:9)
+; CHECK-SAME: from 2 locations. (Found at: <UNKNOWN LOCATION>,
+; CHECK-SAME: <UNKNOWN LOCATION>)
 ; RUN: llc %s -enable-machine-outliner -mtriple=aarch64-unknown-unknown -o /dev/null -pass-remarks-missed=machine-outliner -pass-remarks-output=%t.yaml
 ; RUN: cat %t.yaml | FileCheck %s -check-prefix=YAML
 ; YAML: --- !Missed
 ; YAML-NEXT: Pass:            machine-outliner
 ; YAML-NEXT: Name:            NotOutliningCheaper
-; YAML-NEXT: DebugLoc:        { File: machine-outliner-remarks.ll, Line: 5, Column: 9 }
 ; YAML-NEXT: Function:        dog
 ; YAML-NEXT: Args:            
 ; YAML-NEXT:   - String:          'Did not outline '
@@ -28,8 +27,7 @@
 ; YAML-NEXT:   - NotOutliningCost: '16'
 ; YAML-NEXT:   - String:          ')'
 ; YAML-NEXT:   - String:          ' (Also found at: '
-; YAML-NEXT:   - OtherStartLoc1:  'machine-outliner-remarks.ll:13:9'
-; YAML-NEXT:     DebugLoc:        { File: machine-outliner-remarks.ll, Line: 13, Column: 9 }
+; YAML-NEXT:   - OtherStartLoc1:  '<UNKNOWN LOCATION>'
 ; YAML-NEXT:   - String:          ')'
 ; YAML: --- !Passed
 ; YAML-NEXT: Pass:            machine-outliner
@@ -46,11 +44,9 @@
 ; YAML-NEXT:   - NumOccurrences:  '2'
 ; YAML-NEXT:   - String:          ' locations. '
 ; YAML-NEXT:   - String:          '(Found at: '
-; YAML-NEXT:   - StartLoc0:       'machine-outliner-remarks.ll:36:1'
-; YAML-NEXT:     DebugLoc:        { File: machine-outliner-remarks.ll, Line: 36, Column: 1 }
+; YAML-NEXT:   - StartLoc0:       '<UNKNOWN LOCATION>'
 ; YAML-NEXT:   - String:          ', '
-; YAML-NEXT:   - StartLoc1:       'machine-outliner-remarks.ll:27:9'
-; YAML-NEXT:     DebugLoc:        { File: machine-outliner-remarks.ll, Line: 27, Column: 9 }
+; YAML-NEXT:   - StartLoc1:       '<UNKNOWN LOCATION>'
 ; YAML-NEXT:   - String:          ')'
 
 define void @dog() #0 !dbg !8 {

llvm/test/DebugInfo/ARM/single-constant-use-preserves-dbgloc.ll

@@ -9,9 +9,6 @@
 ;     return -1;
 ; }
 
-; CHECK: .loc 1 6 7
-; CHECK: mvn
-
 target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
 target triple = "armv7--linux-gnueabihf"
 
@@ -33,7 +30,17 @@ if.then:                                          ; preds = %entry
   br label %return, !dbg !18
 
 if.end:                                           ; preds = %entry
+; Materialize the constant.
+; CHECK:      .loc    1 0
+; CHECK-NEXT: mvn     r0, #0
+
+; The backend performs the store to %retval first, for some reason.
+; CHECK-NEXT: .loc    1 7 5
+; CHECK-NEXT: str     r0, [sp, #4]
   store i32 -1, i32* %x, align 4, !dbg !19
+
+; CHECK-NEXT: .loc    1 6 7
+; CHECK-NEXT: str     r0, [sp]
   store i32 -1, i32* %retval, !dbg !20
   br label %return, !dbg !20
 

llvm/test/tools/llvm-objdump/AMDGPU/source-lines.ll

@@ -7,10 +7,10 @@
 ; LINE:      source_lines_test:
 ; LINE-NEXT: ; {{.*}}source-lines.cl:1
 ; Kernel.
-; LINE: ; {{.*}}source-lines.cl:2
 ; LINE: v_mov_b32_e32 v{{[0-9]+}}, 0x777
-; LINE: ; {{.*}}source-lines.cl:3
+; LINE: ; {{.*}}source-lines.cl:2
 ; LINE: v_mov_b32_e32 v{{[0-9]+}}, 0x888
+; LINE: ; {{.*}}source-lines.cl:3
 ; LINE: ; {{.*}}source-lines.cl:4
 ; LINE: v_add_u32_e32
 ; LINE: ; {{.*}}source-lines.cl:5
@@ -23,10 +23,10 @@
 ; SOURCE:      source_lines_test:
 ; SOURCE-NEXT: ; kernel void source_lines_test(global int *Out) {
 ; Kernel.
-; SOURCE: ; int var0 = 0x777;
 ; SOURCE: v_mov_b32_e32 v{{[0-9]+}}, 0x777
-; SOURCE: ; int var1 = 0x888;
+; SOURCE: ; int var0 = 0x777;
 ; SOURCE: v_mov_b32_e32 v{{[0-9]+}}, 0x888
+; SOURCE: ; int var1 = 0x888;
 ; SOURCE: ; int var2 = var0 + var1;
 ; SOURCE: v_add_u32_e32
 ; SOURCE: ; *Out = var2;