[llvm] 3b38314 - Reapply "[InstCombine] Preserve profile after folding select instructions with conditionals" (#161885) (#161890)
via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 3 12:26:13 PDT 2025
Author: Alan Zhao
Date: 2025-10-03T12:26:09-07:00
New Revision: 3b38314a2b69847305b692677dbe64f1eb43235a
URL: https://github.com/llvm/llvm-project/commit/3b38314a2b69847305b692677dbe64f1eb43235a
DIFF: https://github.com/llvm/llvm-project/commit/3b38314a2b69847305b692677dbe64f1eb43235a.diff
LOG: Reapply "[InstCombine] Preserve profile after folding select instructions with conditionals" (#161885) (#161890)
This reverts commit 572b579632fb79ea6eb562a537c9ff1280b3d4f5.
This is a reland of #159666 but with a fix moving the `extern`
declaration of the flag under the LLVM namespace, which is needed to fix
a linker error caused by #161240.
Added:
Modified:
llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
llvm/test/Transforms/InstCombine/select-and-cmp.ll
llvm/test/Transforms/InstCombine/select-or-cmp.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 87000a1c36eef..3df448ddde99c 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -50,6 +50,9 @@
using namespace llvm;
using namespace PatternMatch;
+namespace llvm {
+extern cl::opt<bool> ProfcheckDisableMetadataFixes;
+}
/// Replace a select operand based on an equality comparison with the identity
/// constant of a binop.
@@ -4492,8 +4495,21 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
auto FoldSelectWithAndOrCond = [&](bool IsAnd, Value *A,
Value *B) -> Instruction * {
if (Value *V = simplifySelectInst(B, TrueVal, FalseVal,
- SQ.getWithInstruction(&SI)))
- return SelectInst::Create(A, IsAnd ? V : TrueVal, IsAnd ? FalseVal : V);
+ SQ.getWithInstruction(&SI))) {
+ Value *NewTrueVal = IsAnd ? V : TrueVal;
+ Value *NewFalseVal = IsAnd ? FalseVal : V;
+
+ // If the True and False values don't change, then preserve the branch
+ // metadata of the original select as the net effect of this change is to
+ // simplify the conditional.
+ Instruction *MDFrom = nullptr;
+ if (NewTrueVal == TrueVal && NewFalseVal == FalseVal &&
+ !ProfcheckDisableMetadataFixes) {
+ MDFrom = &SI;
+ }
+ return SelectInst::Create(A, NewTrueVal, NewFalseVal, "", nullptr,
+ MDFrom);
+ }
// Is (select B, T, F) a SPF?
if (CondVal->hasOneUse() && SelType->isIntOrIntVectorTy()) {
diff --git a/llvm/test/Transforms/InstCombine/select-and-cmp.ll b/llvm/test/Transforms/InstCombine/select-and-cmp.ll
index 50e1493cad5c7..26c04ad412445 100644
--- a/llvm/test/Transforms/InstCombine/select-and-cmp.ll
+++ b/llvm/test/Transforms/InstCombine/select-and-cmp.ll
@@ -1,4 +1,4 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
define i32 @select_and_icmp(i32 %x, i32 %y, i32 %z) {
@@ -114,34 +114,34 @@ define i32 @select_and_icmp_inv(i32 %x, i32 %y, i32 %z) {
; Below used to be negative tests in InstSimplify, but are no more negative cases here
-define i32 @select_and_icmp_pred_bad_1(i32 %x, i32 %y, i32 %z) {
+define i32 @select_and_icmp_pred_bad_1(i32 %x, i32 %y, i32 %z) !prof !0 {
; CHECK-LABEL: @select_and_icmp_pred_bad_1(
-; CHECK-NEXT: ret i32 [[X]]
+; CHECK-NEXT: ret i32 [[X:%.*]]
;
%A = icmp eq i32 %x, %z
%B = icmp ne i32 %y, %z
%C = and i1 %A, %B
- %D = select i1 %C, i32 %z, i32 %x
+ %D = select i1 %C, i32 %z, i32 %x, !prof !1
ret i32 %D
}
-define i32 @select_and_icmp_pred_bad_2(i32 %x, i32 %y, i32 %z) {
+define i32 @select_and_icmp_pred_bad_2(i32 %x, i32 %y, i32 %z) !prof !0 {
; CHECK-LABEL: @select_and_icmp_pred_bad_2(
; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[Z]], i32 [[X]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[Z]], i32 [[X:%.*]], !prof [[PROF1:![0-9]+]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp ne i32 %x, %z
%B = icmp eq i32 %y, %z
%C = and i1 %A, %B
- %D = select i1 %C, i32 %z, i32 %x
+ %D = select i1 %C, i32 %z, i32 %x, !prof !1
ret i32 %D
}
define i32 @select_and_icmp_pred_bad_3(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_3(
-; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[X]], i32 [[Z]]
+; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[X:%.*]], i32 [[Z]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp ne i32 %x, %z
@@ -153,8 +153,8 @@ define i32 @select_and_icmp_pred_bad_3(i32 %x, i32 %y, i32 %z) {
define i32 @select_and_icmp_pred_bad_4(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_4(
-; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[Z]], i32 [[X]]
+; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[Z]], i32 [[X:%.*]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp eq i32 %x, %z
@@ -166,7 +166,7 @@ define i32 @select_and_icmp_pred_bad_4(i32 %x, i32 %y, i32 %z) {
define i32 @select_and_icmp_alt_bad_1(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_alt_bad_1(
-; CHECK-NEXT: ret i32 [[Z]]
+; CHECK-NEXT: ret i32 [[Z:%.*]]
;
%A = icmp eq i32 %x, %z
%B = icmp ne i32 %y, %z
@@ -177,8 +177,8 @@ define i32 @select_and_icmp_alt_bad_1(i32 %x, i32 %y, i32 %z) {
define i32 @select_and_icmp_alt_bad_2(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_alt_bad_2(
-; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[X]], i32 [[Z]]
+; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[X:%.*]], i32 [[Z]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp ne i32 %x, %z
@@ -191,8 +191,8 @@ define i32 @select_and_icmp_alt_bad_2(i32 %x, i32 %y, i32 %z) {
define i32 @select_and_icmp_alt_bad_3(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_alt_bad_3(
-; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[Z]], i32 [[X]]
+; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[Z]], i32 [[X:%.*]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp ne i32 %x, %z
@@ -204,8 +204,8 @@ define i32 @select_and_icmp_alt_bad_3(i32 %x, i32 %y, i32 %z) {
define i32 @select_and_icmp_alt_bad_4(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_alt_bad_4(
-; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[X]], i32 [[Z]]
+; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[X:%.*]], i32 [[Z]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp eq i32 %x, %z
@@ -322,3 +322,11 @@ define i32 @select_and_icmp_alt_bad_false_val(i32 %x, i32 %y, i32 %z, i32 %k) {
%D = select i1 %C, i32 %x, i32 %k
ret i32 %D
}
+
+!0 = !{!"function_entry_count", i64 1000}
+!1 = !{!"branch_weights", i32 2, i32 3}
+
+;.
+; CHECK: [[META0:![0-9]+]] = !{!"function_entry_count", i64 1000}
+; CHECK: [[PROF1]] = !{!"branch_weights", i32 2, i32 3}
+;.
diff --git a/llvm/test/Transforms/InstCombine/select-or-cmp.ll b/llvm/test/Transforms/InstCombine/select-or-cmp.ll
index 72a3747c5e405..82b069bc91e88 100644
--- a/llvm/test/Transforms/InstCombine/select-or-cmp.ll
+++ b/llvm/test/Transforms/InstCombine/select-or-cmp.ll
@@ -1,4 +1,4 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
define i32 @select_or_icmp(i32 %x, i32 %y, i32 %z) {
@@ -114,47 +114,47 @@ define i32 @select_or_icmp_inv(i32 %x, i32 %y, i32 %z) {
; Below used to be negative tests in InstSimplify, but are no more negative cases here
-define i32 @select_and_icmp_pred_bad_1(i32 %x, i32 %y, i32 %z) {
+define i32 @select_and_icmp_pred_bad_1(i32 %x, i32 %y, i32 %z) !prof !0 {
; CHECK-LABEL: @select_and_icmp_pred_bad_1(
-; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[X]], i32 [[Z]]
+; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[X:%.*]], i32 [[Z]], !prof [[PROF1:![0-9]+]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp eq i32 %x, %z
%B = icmp ne i32 %y, %z
%C = or i1 %A, %B
- %D = select i1 %C, i32 %z, i32 %x
+ %D = select i1 %C, i32 %z, i32 %x, !prof !1
ret i32 %D
}
-define i32 @select_and_icmp_pred_bad_2(i32 %x, i32 %y, i32 %z) {
+define i32 @select_and_icmp_pred_bad_2(i32 %x, i32 %y, i32 %z) !prof !0 {
; CHECK-LABEL: @select_and_icmp_pred_bad_2(
-; CHECK-NEXT: ret i32 [[Z]]
+; CHECK-NEXT: ret i32 [[Z:%.*]]
;
%A = icmp ne i32 %x, %z
%B = icmp eq i32 %y, %z
%C = or i1 %A, %B
- %D = select i1 %C, i32 %z, i32 %x
+ %D = select i1 %C, i32 %z, i32 %x, !prof !1
ret i32 %D
}
-define i32 @select_and_icmp_pred_bad_3(i32 %x, i32 %y, i32 %z) {
+define i32 @select_and_icmp_pred_bad_3(i32 %x, i32 %y, i32 %z) !prof !0 {
; CHECK-LABEL: @select_and_icmp_pred_bad_3(
-; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[Z]], i32 [[X]]
+; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[Z]], i32 [[X:%.*]], !prof [[PROF2:![0-9]+]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp eq i32 %x, %z
%B = icmp eq i32 %y, %z
%C = or i1 %A, %B
- %D = select i1 %C, i32 %z, i32 %x
+ %D = select i1 %C, i32 %z, i32 %x, !prof !1
ret i32 %D
}
define i32 @select_and_icmp_pred_bad_4(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_pred_bad_4(
-; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[X]], i32 [[Z]]
+; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[X:%.*]], i32 [[Z]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp ne i32 %x, %z
@@ -166,8 +166,8 @@ define i32 @select_and_icmp_pred_bad_4(i32 %x, i32 %y, i32 %z) {
define i32 @select_or_icmp_alt_bad_1(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp_alt_bad_1(
-; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[Z]], i32 [[X]]
+; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[Z]], i32 [[X:%.*]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp eq i32 %x, %z
@@ -179,7 +179,7 @@ define i32 @select_or_icmp_alt_bad_1(i32 %x, i32 %y, i32 %z) {
define i32 @select_or_icmp_alt_bad_2(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp_alt_bad_2(
-; CHECK-NEXT: ret i32 [[X]]
+; CHECK-NEXT: ret i32 [[X:%.*]]
;
%A = icmp ne i32 %x, %z
%B = icmp eq i32 %y, %z
@@ -190,8 +190,8 @@ define i32 @select_or_icmp_alt_bad_2(i32 %x, i32 %y, i32 %z) {
define i32 @select_or_icmp_alt_bad_3(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp_alt_bad_3(
-; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[X]], i32 [[Z]]
+; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B]], i32 [[X:%.*]], i32 [[Z]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp eq i32 %x, %z
@@ -203,8 +203,8 @@ define i32 @select_or_icmp_alt_bad_3(i32 %x, i32 %y, i32 %z) {
define i32 @select_or_icmp_alt_bad_4(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp_alt_bad_4(
-; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
-; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[Z]], i32 [[X]]
+; CHECK-NEXT: [[B_NOT:%.*]] = icmp eq i32 [[Y:%.*]], [[Z:%.*]]
+; CHECK-NEXT: [[D:%.*]] = select i1 [[B_NOT]], i32 [[Z]], i32 [[X:%.*]]
; CHECK-NEXT: ret i32 [[D]]
;
%A = icmp ne i32 %x, %z
@@ -321,3 +321,11 @@ define i32 @select_or_icmp_alt_bad_false_val(i32 %x, i32 %y, i32 %z, i32 %k) {
%D = select i1 %C, i32 %x, i32 %k
ret i32 %D
}
+
+!0 = !{!"function_entry_count", i64 1000}
+!1 = !{!"branch_weights", i32 2, i32 3}
+;.
+; CHECK: [[META0:![0-9]+]] = !{!"function_entry_count", i64 1000}
+; CHECK: [[PROF1]] = !{!"branch_weights", i32 3, i32 2}
+; CHECK: [[PROF2]] = !{!"branch_weights", i32 2, i32 3}
+;.
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