[InstCombine] Add function attribute instcombine-no-verify-fixpoint (#113822)

This patch introduces a function attribute
`instcombine-no-verify-fixpoint` to avoids disabling fix-point
verification for unrelated tests in the same file.
Address comment
#112642 (comment).

Author: dtcxzyw

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -5464,6 +5464,8 @@ static bool combineInstructionsOverFunction(
     BranchProbabilityInfo *BPI, ProfileSummaryInfo *PSI,
     const InstCombineOptions &Opts) {
   auto &DL = F.getDataLayout();
+  bool VerifyFixpoint = Opts.VerifyFixpoint &&
+                        !F.hasFnAttribute("instcombine-no-verify-fixpoint");
 
   /// Builder - This is an IRBuilder that automatically inserts new
   /// instructions into the worklist when they are created.
@@ -5488,7 +5490,7 @@ static bool combineInstructionsOverFunction(
   while (true) {
     ++Iteration;
 
-    if (Iteration > Opts.MaxIterations && !Opts.VerifyFixpoint) {
+    if (Iteration > Opts.MaxIterations && !VerifyFixpoint) {
       LLVM_DEBUG(dbgs() << "\n\n[IC] Iteration limit #" << Opts.MaxIterations
                         << " on " << F.getName()
                         << " reached; stopping without verifying fixpoint\n");
@@ -5510,9 +5512,11 @@ static bool combineInstructionsOverFunction(
     MadeIRChange = true;
     if (Iteration > Opts.MaxIterations) {
       report_fatal_error(
-          "Instruction Combining did not reach a fixpoint after " +
-              Twine(Opts.MaxIterations) + " iterations. " +
-              "Use 'instcombine<no-verify-fixpoint>' to suppress this error.",
+          "Instruction Combining on " + Twine(F.getName()) +
+              " did not reach a fixpoint after " + Twine(Opts.MaxIterations) +
+              " iterations. " +
+              "Use 'instcombine<no-verify-fixpoint>' or function attribute "
+              "'instcombine-no-verify-fixpoint' to suppress this error.",
           /*GenCrashDiag=*/false);
     }
   }

llvm/test/Analysis/ValueTracking/numsignbits-from-assume.ll

@@ -1,8 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -passes='instcombine<no-verify-fixpoint>' -S | FileCheck %s
-
-; FIXME: This does not currently reach a fix point, because an assume can only
-; be propagated backwards after its argument has been simplified.
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
 
 define i32 @computeNumSignBits_add1(i32 %in) {
 ; CHECK-LABEL: @computeNumSignBits_add1(

llvm/test/Transforms/InstCombine/2007-10-31-RangeCrash.ll

@@ -1,13 +1,14 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
-; RUN: opt < %s -S -passes='instcombine<no-verify-fixpoint>' | FileCheck %s
+; RUN: opt < %s -S -passes=instcombine | FileCheck %s
 
 ; We do not reach a fixpoint, because we first have to infer nsw on the IV add,
 ; and could eliminate the icmp slt afterwards, but don't revisit it.
 
 target datalayout = "E-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f128:64:128"
 
-define i32 @test() {
-; CHECK-LABEL: define i32 @test() {
+define i32 @test() "instcombine-no-verify-fixpoint" {
+; CHECK-LABEL: define i32 @test(
+; CHECK-SAME: ) #[[ATTR0:[0-9]+]] {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br i1 true, label [[BB_I:%.*]], label [[CALCULATECOLORSPECIFICBLACKLEVEL_EXIT:%.*]]
 ; CHECK:       bb.i:

llvm/test/Transforms/InstCombine/cast_phi.ll

@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -passes="instcombine<no-verify-fixpoint>" -S | FileCheck %s
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
 
 target datalayout = "n32:64"
 
@@ -309,7 +309,7 @@ exit:
   ret i64 %r
 }
 
-define i8 @trunc_in_loop_exit_block() {
+define i8 @trunc_in_loop_exit_block() "instcombine-no-verify-fixpoint" {
 ; CHECK-LABEL: @trunc_in_loop_exit_block(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]

llvm/test/Transforms/InstCombine/constant-fold-iteration.ll

@@ -1,11 +1,12 @@
-; RUN: opt < %s -passes='instcombine<no-verify-fixpoint>' -S -debug 2>&1 | FileCheck %s
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -passes=instcombine -S -debug 2>&1 | FileCheck %s
 ; REQUIRES: asserts
 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32"
 
 ; This test disables fixpoint verification, because that would cause a second
 ; iteration for verification.
 
-define i32 @a() nounwind readnone {
+define i32 @a() nounwind readnone "instcombine-no-verify-fixpoint" {
 entry:
   %cmp = icmp eq i32 0, ptrtoint (ptr @a to i32)
   %ext = zext i1 %cmp to i32

llvm/test/Transforms/InstCombine/icmp-or.ll

@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -passes='instcombine<no-verify-fixpoint>' -S | FileCheck %s
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
 
 declare void @use(i8)
 
@@ -432,7 +432,7 @@ define i1 @icmp_or_xor_2_ne_fail(i64 %x1, i64 %y1, i64 %x2, i64 %y2) {
 ; simplify `%cmp_1 = icmp eq i64 %xor, 0`, `%xor = xor i64 %x1, %y1`
 ; has one use which allows for complete simplification (rooted on
 ; `%or1 = or i1 %cmp, %cmp_1` so we don't end up adding it back).
-define i1 @icmp_or_xor_2_3_fail(i64 %x1, i64 %y1, i64 %x2, i64 %y2) {
+define i1 @icmp_or_xor_2_3_fail(i64 %x1, i64 %y1, i64 %x2, i64 %y2) "instcombine-no-verify-fixpoint" {
 ; CHECK-LABEL: @icmp_or_xor_2_3_fail(
 ; CHECK-NEXT:    [[XOR:%.*]] = xor i64 [[X1:%.*]], [[Y1:%.*]]
 ; CHECK-NEXT:    [[XOR1:%.*]] = xor i64 [[X2:%.*]], [[Y2:%.*]]
@@ -453,7 +453,7 @@ define i1 @icmp_or_xor_2_3_fail(i64 %x1, i64 %y1, i64 %x2, i64 %y2) {
 
 ; negative test - xor multiuse
 
-define i1 @icmp_or_xor_2_4_fail(i64 %x1, i64 %y1, i64 %x2, i64 %y2) {
+define i1 @icmp_or_xor_2_4_fail(i64 %x1, i64 %y1, i64 %x2, i64 %y2) "instcombine-no-verify-fixpoint" {
 ; CHECK-LABEL: @icmp_or_xor_2_4_fail(
 ; CHECK-NEXT:    [[XOR:%.*]] = xor i64 [[X1:%.*]], [[Y1:%.*]]
 ; CHECK-NEXT:    [[XOR1:%.*]] = xor i64 [[X2:%.*]], [[Y2:%.*]]

llvm/test/Transforms/InstCombine/pr55228.ll

@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -passes='instcombine<no-verify-fixpoint>' < %s | FileCheck %s
+; RUN: opt -S -passes=instcombine < %s | FileCheck %s
 
 ; This does not reach a fixpoint, because the global initializer is not in
 ; folded form. This will not happen if preceded by a GlobalOpt run.
@@ -9,7 +9,7 @@ target datalayout = "p:8:8"
 @g = external global i8
 @c = constant ptr getelementptr inbounds (i8, ptr @g, i64 1)
 
-define i1 @test(ptr %p) {
+define i1 @test(ptr %p) "instcombine-no-verify-fixpoint" {
 ; CHECK-LABEL: @test(
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp eq ptr [[P:%.*]], getelementptr inbounds (i8, ptr @g, i64 1)
 ; CHECK-NEXT:    ret i1 [[CMP]]

llvm/test/Transforms/InstCombine/shift.ll

@@ -1,8 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -passes='instcombine<no-verify-fixpoint>' -S | FileCheck %s
-
-; The fuzzer-generated @ashr_out_of_range test case does not reach a fixpoint,
-; because a logical and it not relaxed to a bitwise and in one iteration.
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
 
 declare void @use(i64)
 declare void @use_i32(i32)
@@ -1735,9 +1732,12 @@ define i177 @lshr_out_of_range2(i177 %Y, ptr %A2, ptr %ptr) {
   ret i177 %B1
 }
 
+; The fuzzer-generated @ashr_out_of_range test case does not reach a fixpoint,
+; because a logical and it not relaxed to a bitwise and in one iteration.
+
 ; OSS Fuzz #5032
 ; https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5032
-define void @ashr_out_of_range(ptr %A) {
+define void @ashr_out_of_range(ptr %A) "instcombine-no-verify-fixpoint" {
 ; CHECK-LABEL: @ashr_out_of_range(
 ; CHECK-NEXT:    [[L:%.*]] = load i177, ptr [[A:%.*]], align 4
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp eq i177 [[L]], -1

llvm/test/Transforms/InstCombine/sink_instruction.ll

@@ -1,9 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -passes='instcombine<no-verify-fixpoint>' -S < %s | FileCheck %s
-
-; We fail to reach a fixpoint, because sunk instructions get revisited too
-; early. In @test2 the sunk add is revisited before the dominating condition
-; is visited and added to the DomConditionCache.
+; RUN: opt -passes=instcombine -S < %s | FileCheck %s
 
 ;; This tests that the instructions in the entry blocks are sunk into each
 ;; arm of the 'if'.
@@ -31,9 +27,12 @@ endif:          ; preds = %entry
   ret i32 %tmp.2
 }
 
+; We fail to reach a fixpoint, because sunk instructions get revisited too
+; early. In @test2 the sunk add is revisited before the dominating condition
+; is visited and added to the DomConditionCache.
 
 ;; PHI use, sink divide before call.
-define i32 @test2(i32 %x) nounwind ssp {
+define i32 @test2(i32 %x) nounwind ssp "instcombine-no-verify-fixpoint" {
 ; CHECK-LABEL: @test2(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[BB:%.*]]

llvm/test/Transforms/InstCombine/zext-or-icmp.ll

@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -passes='instcombine<no-verify-fixpoint>' -S | FileCheck %s
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
 
 define i8 @zext_or_icmp_icmp(i8 %a, i8 %b) {
 ; CHECK-LABEL: @zext_or_icmp_icmp(
@@ -168,7 +168,7 @@ define i32 @PR49475(i32 %x, i16 %y) {
 
 ; This would infinite-loop.
 
-define i8 @PR49475_infloop(i32 %t0, i16 %insert, i64 %e, i8 %i162) {
+define i8 @PR49475_infloop(i32 %t0, i16 %insert, i64 %e, i8 %i162) "instcombine-no-verify-fixpoint" {
 ; CHECK-LABEL: @PR49475_infloop(
 ; CHECK-NEXT:    [[B2:%.*]] = icmp eq i16 [[INSERT:%.*]], 0
 ; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[T0:%.*]], 1

llvm/test/Transforms/PGOProfile/chr.ll

@@ -1,8 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -passes='require<profile-summary>,function(chr,instcombine<no-verify-fixpoint>,simplifycfg)' -S | FileCheck %s
-
-; FIXME: This does not currently reach a fix point, because we don't make use
-; of a freeze that is pushed up the instruction chain later.
+; RUN: opt < %s -passes='require<profile-summary>,function(chr,instcombine,simplifycfg)' -S | FileCheck %s
 
 declare void @foo()
 declare void @bar()
@@ -1910,6 +1907,9 @@ bb4:
   ret i32 %v13
 }
 
+; FIXME: This does not currently reach a fix point, because we don't make use
+; of a freeze that is pushed up the instruction chain later.
+
 ; Test the case where two scopes share a common instruction to hoist (%cmp.i).
 ; Two scopes would hoist it to their hoist points, but since the outer scope
 ; hoists (entry/bb6-9) it first to its hoist point, it'd be wrong (causing bad
@@ -1928,7 +1928,7 @@ bb4:
 ;     foo();
 ;  }
 ;  return 45;
-define i32 @test_chr_21(i64 %i, i64 %k, i64 %j) !prof !14 {
+define i32 @test_chr_21(i64 %i, i64 %k, i64 %j) "instcombine-no-verify-fixpoint" !prof !14 {
 ; CHECK-LABEL: @test_chr_21(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[I_FR:%.*]] = freeze i64 [[I:%.*]]

llvm/test/Transforms/SimpleLoopUnswitch/2007-08-01-LCSSA.ll

@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
-; RUN: opt < %s -S -passes='loop(simple-loop-unswitch),instcombine<no-verify-fixpoint>' -verify-memoryssa | FileCheck %s
+; RUN: opt < %s -S -passes='loop(simple-loop-unswitch),instcombine' -verify-memoryssa | FileCheck %s
 
 ; We do not reach a fixpoint, because we first have to infer nsw on the IV add,
 ; and could eliminate the icmp slt afterwards, but don't revisit it.
@@ -8,9 +8,9 @@
 
 declare i32 @strcmp(ptr, ptr)
 
-define i32 @_ZN9Generator6strregEPKc(ptr %this, ptr %s) {
+define i32 @_ZN9Generator6strregEPKc(ptr %this, ptr %s) "instcombine-no-verify-fixpoint" {
 ; CHECK-LABEL: define i32 @_ZN9Generator6strregEPKc(
-; CHECK-SAME: ptr [[THIS:%.*]], ptr [[S:%.*]]) {
+; CHECK-SAME: ptr [[THIS:%.*]], ptr [[S:%.*]]) #[[ATTR0:[0-9]+]] {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[TMP122:%.*]] = icmp eq ptr [[S]], null
 ; CHECK-NEXT:    br label [[BB184:%.*]]