diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -703,6 +703,13 @@
       return;
     }
 
+    if (V->getType()->isPointerTy()) {
+      if (RetainedKnowledge RK = getKnowledgeValidInContext(
+              V, {Attribute::Alignment}, Q.CxtI, Q.DT, Q.AC)) {
+        Known.Zero.setLowBits(Log2_32(RK.ArgValue));
+      }
+    }
+
     // The remaining tests are all recursive, so bail out if we hit the limit.
     if (Depth == MaxAnalysisRecursionDepth)
       continue;
@@ -1955,7 +1962,7 @@
   // Aligned pointers have trailing zeros - refine Known.Zero set
   if (isa<PointerType>(V->getType())) {
     Align Alignment = V->getPointerAlignment(Q.DL);
-    Known.Zero.setLowBits(countTrailingZeros(Alignment.value()));
+    Known.Zero.setLowBits(Log2(Alignment));
   }
 
   // computeKnownBitsFromAssume strictly refines Known.
diff --git a/llvm/test/Analysis/BasicAA/featuretest.ll b/llvm/test/Analysis/BasicAA/featuretest.ll
--- a/llvm/test/Analysis/BasicAA/featuretest.ll
+++ b/llvm/test/Analysis/BasicAA/featuretest.ll
@@ -128,7 +128,7 @@
 ; USE_ASSUME-LABEL: @gep_distance_test3(
 ; USE_ASSUME-NEXT:    [[C1:%.*]] = getelementptr i32, i32* [[A:%.*]], i64 1
 ; USE_ASSUME-NEXT:    [[C:%.*]] = bitcast i32* [[C1]] to i8*
-; USE_ASSUME-NEXT:    store i8 42, i8* [[C]], align 1
+; USE_ASSUME-NEXT:    store i8 42, i8* [[C]], align 4
 ; USE_ASSUME-NEXT:    call void @llvm.assume(i1 true) [ "dereferenceable"(i32* [[A]], i64 4), "nonnull"(i32* [[A]]), "align"(i32* [[A]], i64 4) ]
 ; USE_ASSUME-NEXT:    ret i32 0
 ;
diff --git a/llvm/test/Analysis/ValueTracking/assume-queries-counter.ll b/llvm/test/Analysis/ValueTracking/assume-queries-counter.ll
--- a/llvm/test/Analysis/ValueTracking/assume-queries-counter.ll
+++ b/llvm/test/Analysis/ValueTracking/assume-queries-counter.ll
@@ -2,8 +2,8 @@
 
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -instcombine --debug-counter=assume-queries-counter-skip=0,assume-queries-counter-count=1 -S | FileCheck %s --check-prefixes=SAME,COUNTER1
-; RUN: opt < %s -instcombine --debug-counter=assume-queries-counter-skip=1,assume-queries-counter-count=2 -S | FileCheck %s --check-prefixes=SAME,COUNTER2
-; RUN: opt < %s -instcombine --debug-counter=assume-queries-counter-skip=2,assume-queries-counter-count=1 -S | FileCheck %s --check-prefixes=SAME,COUNTER3
+; RUN: opt < %s -instcombine --debug-counter=assume-queries-counter-skip=1,assume-queries-counter-count=4 -S | FileCheck %s --check-prefixes=SAME,COUNTER2
+; RUN: opt < %s -instcombine --debug-counter=assume-queries-counter-skip=6,assume-queries-counter-count=1 -S | FileCheck %s --check-prefixes=SAME,COUNTER3
 
 declare i1 @get_val()
 declare void @llvm.assume(i1)
diff --git a/llvm/unittests/Analysis/ValueTrackingTest.cpp b/llvm/unittests/Analysis/ValueTrackingTest.cpp
--- a/llvm/unittests/Analysis/ValueTrackingTest.cpp
+++ b/llvm/unittests/Analysis/ValueTrackingTest.cpp
@@ -19,6 +19,7 @@
 #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;
@@ -938,6 +939,35 @@
   }
 }
 
+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"