[DebugInfo] Salvage integer literals

(cherry picked from commit 16c57ae)

Author: Snowy1803

lib/SILOptimizer/Utils/InstOptUtils.cpp

@@ -1923,6 +1923,25 @@ void swift::salvageDebugInfo(SILInstruction *I) {
         }
       }
   }
+
+  if (auto *IL = dyn_cast<IntegerLiteralInst>(I)) {
+    APInt value = IL->getValue();
+    const SILDIExprElement ExprElements[2] = {
+      SILDIExprElement::createOperator(value.isNegative() ?
+        SILDIExprOperator::ConstSInt : SILDIExprOperator::ConstUInt),
+      SILDIExprElement::createConstInt(value.getLimitedValue()),
+    };
+    for (Operand *U : getDebugUses(IL)) {
+      auto *DbgInst = cast<DebugValueInst>(U->getUser());
+      auto VarInfo = DbgInst->getVarInfo();
+      if (!VarInfo)
+        continue;
+      VarInfo->DIExpr.prependElements(ExprElements);
+      // Create a new debug_value, with undef, and the correct const int
+      SILBuilder(DbgInst, DbgInst->getDebugScope())
+        .createDebugValue(DbgInst->getLoc(), SILUndef::get(IL), *VarInfo);
+    }
+  }
 }
 
 void swift::salvageLoadDebugInfo(LoadOperation load) {

test/DebugInfo/salvage-integer-literal.swift

@@ -0,0 +1,13 @@
+// RUN: %target-swift-frontend -O -g -emit-sil %s | %FileCheck %s
+
+// In optimized code, a + b will be folded to 5, but we should still keep their
+// debug values.
+
+// CHECK-LABEL: sil
+public func f() -> Int {
+  let a = 2
+  let b = 3
+  // CHECK: debug_value undef : $Builtin.Int64, let, name "a", type $Int, expr op_constu:2:op_fragment:#Int._value
+  // CHECK: debug_value undef : $Builtin.Int64, let, name "b", type $Int, expr op_constu:3:op_fragment:#Int._value
+  return a + b
+}

test/SILOptimizer/dead_array_elim.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -O -emit-sil -primary-file %s | %FileCheck %s
+// RUN: %target-swift-frontend -O -emit-sil -primary-file %s | grep -v debug_value | %FileCheck %s
 
 // REQUIRES: swift_stdlib_no_asserts
 // REQUIRES: swift_in_compiler
@@ -62,9 +62,7 @@ func testDeadArrayElimWithAddressOnlyValues<T>(x: T, y: T) {
 // RLE needs to handle the new init pattern - rdar://117751668
 // TODO-LABEL: sil hidden {{.*}}@$s15dead_array_elim31testDeadArrayAfterOptimizationsySiSSF
 // TODO:      bb0(%0 : $String):
-// TODO-NEXT:   debug_value
 // TODO-NEXT:   integer_literal $Builtin.Int{{[0-9]+}}, 21
-// TODO-NEXT:   debug_value
 // TODO-NEXT:   struct $Int
 // TODO-NEXT:   return
 // TODO:      } // end sil function '$s15dead_array_elim31testDeadArrayAfterOptimizationsySiSSF'
@@ -85,7 +83,6 @@ func testDeadArrayAfterOptimizations(_ stringParameter: String) -> Int {
 // CHECK-LABEL: sil hidden @$s15dead_array_elim15testNestedArraySiyF
 // CHECK:      bb0:
 // CHECK-NEXT:   integer_literal $Builtin.Int{{[0-9]+}}, 3
-// CHECK-NEXT:   debug_value
 // CHECK-NEXT:   struct $Int
 // CHECK-NEXT:   return
 // CHECK:      } // end sil function '$s15dead_array_elim15testNestedArraySiyF'

test/SILOptimizer/optionset.swift

@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend  -parse-as-library -primary-file %s -O -sil-verify-all -module-name=test -emit-sil | %FileCheck %s
-// RUN: %target-swift-frontend  -parse-as-library -primary-file %s -Osize -sil-verify-all -module-name=test -emit-sil | %FileCheck %s
+// RUN: %target-swift-frontend  -parse-as-library -primary-file %s -O -sil-verify-all -module-name=test -emit-sil | grep -v debug_value | %FileCheck %s
+// RUN: %target-swift-frontend  -parse-as-library -primary-file %s -Osize -sil-verify-all -module-name=test -emit-sil | grep -v debug_value | %FileCheck %s
 // REQUIRES: swift_stdlib_no_asserts,optimized_stdlib
 // REQUIRES: swift_in_compiler