[Polly][DebugInfo] Use getStableDebugLoc to avoid intrinsic-dependent behaviour (#81246)

Polly currently uses `getDebugLoc` in a few places to produce diagnostic
output; this is correct when interacting with specific instructions, but
may be incorrect when dealing with instruction ranges if debug
intrinsics are included. As a general rule, the debug locations attached
to debug intrinsics may be misleading compared to the surrounding
instructions, and are not generally used for anything other than
determining variable scope info; the recommended approach is therefore
to use `getStableDebugLoc` instead, which skips over debug intrinsics.
This is necessary to fix test failures that occur when enabling
non-instruction debug info, which removes debug intrinsics from basic
blocks and thus alters the diagnostic output of Polly (despite causing
no functional change).

Author: SLTozer

polly/lib/Analysis/ScopDetectionDiagnostic.cpp

@@ -122,7 +122,7 @@ void getDebugLocations(const BBPair &P, DebugLoc &Begin, DebugLoc &End) {
       continue;
     Todo.append(succ_begin(BB), succ_end(BB));
     for (const Instruction &Inst : *BB) {
-      DebugLoc DL = Inst.getDebugLoc();
+      DebugLoc DL = Inst.getStableDebugLoc();
       if (!DL)
         continue;
 
@@ -821,7 +821,7 @@ std::string ReportUnprofitable::getEndUserMessage() const {
 const DebugLoc &ReportUnprofitable::getDebugLoc() const {
   for (const BasicBlock *BB : R->blocks())
     for (const Instruction &Inst : *BB)
-      if (const DebugLoc &DL = Inst.getDebugLoc())
+      if (const DebugLoc &DL = Inst.getStableDebugLoc())
         return DL;
 
   return R->getEntry()->getTerminator()->getDebugLoc();

polly/lib/Support/ScopLocation.cpp

@@ -25,7 +25,7 @@ void getDebugLocation(const Region *R, unsigned &LineBegin, unsigned &LineEnd,
 
   for (const BasicBlock *BB : R->blocks())
     for (const Instruction &Inst : *BB) {
-      DebugLoc DL = Inst.getDebugLoc();
+      DebugLoc DL = Inst.getStableDebugLoc();
       if (!DL)
         continue;
 

polly/test/ScopDetectionDiagnostics/ReportLoopBound-01.ll

@@ -19,20 +19,20 @@
 
 ; If we reject non-affine loops the non-affine loop bound will be reported:
 ;
-; REJECTNONAFFINELOOPS: remark: ReportLoopBound-01.c:1:12: The following errors keep this region from being a Scop.
+; REJECTNONAFFINELOOPS: remark: ReportLoopBound-01.c:2:8: The following errors keep this region from being a Scop.
 ; REJECTNONAFFINELOOPS: remark: ReportLoopBound-01.c:2:8: Failed to derive an affine function from the loop bounds.
 ; REJECTNONAFFINELOOPS: remark: ReportLoopBound-01.c:3:5: Invalid Scop candidate ends here.
 
 ; If we allow non-affine loops the non-affine access will be reported:
 ;
-; ALLOWNONAFFINELOOPS: remark: ReportLoopBound-01.c:1:12: The following errors keep this region from being a Scop.
+; ALLOWNONAFFINELOOPS: remark: ReportLoopBound-01.c:2:8: The following errors keep this region from being a Scop.
 ; ALLOWNONAFFINELOOPS: remark: ReportLoopBound-01.c:3:5: The array subscript of "A" is not affine
 ; ALLOWNONAFFINELOOPS: remark: ReportLoopBound-01.c:3:5: Invalid Scop candidate ends here.
 
 ; If we allow non-affine loops and non-affine accesses the region will be reported as not profitable:
 ;
-; ALLOWNONAFFINEALL: remark: ReportLoopBound-01.c:1:12: The following errors keep this region from being a Scop.
-; ALLOWNONAFFINEALL: remark: ReportLoopBound-01.c:1:12: No profitable polyhedral optimization found
+; ALLOWNONAFFINEALL: remark: ReportLoopBound-01.c:2:8: The following errors keep this region from being a Scop.
+; ALLOWNONAFFINEALL: remark: ReportLoopBound-01.c:2:8: No profitable polyhedral optimization found
 ; ALLOWNONAFFINEALL: remark: ReportLoopBound-01.c:3:5: Invalid Scop candidate ends here.
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"

polly/test/ScopDetectionDiagnostics/loop_has_multiple_exits.ll

@@ -2,7 +2,7 @@
 ;
 ; Derived from test-suite/MultiSource/Benchmarks/BitBench/uuencode/uuencode.c
 ;
-; CHECK: remark: uuencode.c:75:18: The following errors keep this region from being a Scop.
+; CHECK: remark: uuencode.c:76:13: The following errors keep this region from being a Scop.
 ; CHECK: remark: uuencode.c:83:3: Loop cannot be handled because it has multiple exits.
 ; CHECK: remark: uuencode.c:95:21: Invalid Scop candidate ends here.