[profcheck] Propagate profile metadata in trunc(select) transform (llvm#162406)

In the `AggressiveInstCombine` pass, profile metadata was being dropped during the transformation of `trunc(select(...))` operations. This change fixes the issue by propagating the metadata from the original `select` to the new `trunc-select` instruction.

Author: jinhuang1102

llvm/lib/Transforms/AggressiveInstCombine/TruncInstCombine.cpp

@@ -459,7 +459,7 @@ void TruncInstCombine::ReduceExpressionGraph(Type *SclTy) {
       Value *Op0 = I->getOperand(0);
       Value *LHS = getReducedOperand(I->getOperand(1), SclTy);
       Value *RHS = getReducedOperand(I->getOperand(2), SclTy);
-      Res = Builder.CreateSelect(Op0, LHS, RHS);
+      Res = Builder.CreateSelect(Op0, LHS, RHS, "", I);
       break;
     }
     case Instruction::PHI: {

llvm/test/Transforms/AggressiveInstCombine/trunc_select.ll

@@ -3,16 +3,17 @@
 
 target datalayout = "e-m:m-p1:64:64:64-p:32:32:32-n8:16:32"
 
-define dso_local i16 @select_i16(i16 %a, i16 %b, i1 %cond) {
+define dso_local i16 @select_i16(i16 %a, i16 %b, i1 %cond) !prof !0 {
 ; CHECK-LABEL: @select_i16(
+; CHECK: !prof [[PROF_0:![0-9]+]] {
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], i16 [[A:%.*]], i16 [[B:%.*]]
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], i16 [[A:%.*]], i16 [[B:%.*]], !prof [[PROF_1:![0-9]+]]
 ; CHECK-NEXT:    ret i16 [[SEL]]
 ;
 entry:
   %conv0 = sext i16 %a to i32
   %conv1 = sext i16 %b to i32
-  %sel = select i1 %cond, i32 %conv0, i32 %conv1
+  %sel = select i1 %cond, i32 %conv0, i32 %conv1, !prof !1
   %conv4 = trunc i32 %sel to i16
   ret i16 %conv4
 }
@@ -134,3 +135,8 @@ entry:
   ret i16 %conv4
 }
 
+!0 = !{!"function_entry_count", i64 1000}
+!1 = !{!"branch_weights", i32 2, i32 3}
+; CHECK: [[PROF_0]] = !{!"function_entry_count", i64 1000}
+; CHECK: [[PROF_1]] = !{!"branch_weights", i32 2, i32 3}
+

llvm/test/Transforms/AggressiveInstCombine/trunc_select_cmp.ll

@@ -1,19 +1,20 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -passes=aggressive-instcombine -S | FileCheck %s
 
-define dso_local i16 @cmp_select_sext_const(i8 %a) {
+define dso_local i16 @cmp_select_sext_const(i8 %a) !prof !0 {
 ; CHECK-LABEL: @cmp_select_sext_const(
+; CHECK: !prof [[PROF_0:![0-9]+]] {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CONV:%.*]] = sext i8 [[A:%.*]] to i32
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[CONV]], 109
-; CHECK-NEXT:    [[COND:%.*]] = select i1 [[CMP]], i32 109, i32 [[CONV]]
+; CHECK-NEXT:    [[COND:%.*]] = select i1 [[CMP]], i32 109, i32 [[CONV]], !prof [[PROF_1:![0-9]+]]
 ; CHECK-NEXT:    [[CONV4:%.*]] = trunc i32 [[COND]] to i16
 ; CHECK-NEXT:    ret i16 [[CONV4]]
 ;
 entry:
   %conv = sext i8 %a to i32
   %cmp = icmp slt i32 %conv, 109
-  %cond = select i1 %cmp, i32 109, i32 %conv
+  %cond = select i1 %cmp, i32 109, i32 %conv, !prof !1
   %conv4 = trunc i32 %cond to i16
   ret i16 %conv4
 }
@@ -209,3 +210,7 @@ define i16 @cmp_select_unsigned_const_i16Const_noTransformation(i8 %a) {
   ret i16 %conv4
 }
 
+!0 = !{!"function_entry_count", i64 1000}
+!1 = !{!"branch_weights", i32 2, i32 3}
+; CHECK: [[PROF_0]] = !{!"function_entry_count", i64 1000}
+; CHECK: [[PROF_1]] = !{!"branch_weights", i32 2, i32 3}