[ValuteTracking] Handle alignment assume bundles

[arichardson]

Summary

I noticed that alignment was no longer inferred as well after I recently merged
our CHERI fork from upstream. It seems this was caused by the change to move
IRBuilder's alignment assumptions over to assume bundles instead of
icmp+ptrtoint+mask (D71739).

[jdoerfert]

LGTM "but" already "fixed" in D88669. we need to merge one of the two, they basically do the same thing. We should make sure to merge all tests ;)

llvm/lib/Analysis/ValueTracking.cpp

1965 ↗

(On Diff #299490)

Unrelated but LGTM.

[jdoerfert]

Can you merge D88669, and then your unrelated change as well as your unit test?

[arichardson]

In D89830#2347533, @jdoerfert wrote:

Can you merge D88669, and then your unrelated change as well as your unit test?

Sure. Alternatively you could commit D88669 and I'll update this to just add the test + the unrelated cleanup?

[jdoerfert]

In D89830#2347544, @arichardson wrote:

In D89830#2347533, @jdoerfert wrote:

Can you merge D88669, and then your unrelated change as well as your unit test?

Sure. Alternatively you could commit D88669 and I'll update this to just add the test + the unrelated cleanup?

I don't have a clean master to test right now. Still trying to hunt down a different problem. Can try to do it later today but feel free to go ahead w/o me.
D88669 has the author's name/email in a comment.

[jdoerfert]

Thanks!

llvm/unittests/Analysis/ValueTrackingTest.cpp

 #include "llvm/IR/Function.h"
 #include "llvm/IR/InstIterator.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/KnownBits.h"
 #include "llvm/Support/SourceMgr.h"
+#include "llvm/Transforms/Utils/Local.h"
 #include "gtest/gtest.h"
 
 using namespace llvm;
 
 namespace {
 
 static Instruction *findInstructionByNameOrNull(Function *F, StringRef Name) {
   for (Instruction &I : instructions(F))
EXPECT_EQ(canCreatePoison(cast<Operator>(&I)), Poison)
         << " = " << I;
     EXPECT_EQ(canCreateUndefOrPoison(cast<Operator>(&I)), Undef || Poison)
         << "Incorrect answer of canCreateUndef at instruction " << Index
         << " = " << I;
     Index++;
   }
 }
 
+TEST_F(ValueTrackingTest, computePtrAlignment) {
+  parseAssembly("declare i1 @f_i1()\n"
+                "declare i8* @f_i8p()\n"
+                "declare void @llvm.assume(i1)\n"
+                "define void @test() {\n"
+                "  %A = call i8* @f_i8p()\n"
+                "  %cond = call i1 @f_i1()\n"
+                "  %CxtI = add i32 0, 0\n"
+                "  br i1 %cond, label %BB1, label %EXIT\n"
+                "BB1:\n"
+                "  %CxtI2 = add i32 0, 0\n"
+                "  %cond2 = call i1 @f_i1()\n"
+                "  call void @llvm.assume(i1 true) [ \"align\"(i8* %A, i64 16) ]\n"
+                "  br i1 %cond2, label %BB2, label %EXIT\n"
+                "BB2:\n"
+                "  %CxtI3 = add i32 0, 0\n"
+                "  ret void\n"
+                "EXIT:\n"
+                "  ret void\n"
+                "}");
+  AssumptionCache AC(*F);
+  DominatorTree DT(*F);
+  DataLayout DL = M->getDataLayout();
+  EXPECT_EQ(getKnownAlignment(A, DL, CxtI, &AC, &DT), Align(1));
+  EXPECT_EQ(getKnownAlignment(A, DL, CxtI2, &AC, &DT), Align(1));
+  EXPECT_EQ(getKnownAlignment(A, DL, CxtI3, &AC, &DT), Align(16));
+}
+
 TEST_F(ComputeKnownBitsTest, ComputeKnownBits) {
   parseAssembly(
       "define i32 @test(i32 %a, i32 %b) {\n"
       "  %ash = mul i32 %a, 8\n"
       "  %aad = add i32 %ash, 7\n"
       "  %aan = and i32 %aad, 4095\n"
       "  %bsh = shl i32 %b, 4\n"
       "  %bad = or i32 %bsh, 6\n"