[ValueTracking] Improve isImpliedCondition for matching LHS and Imm RHSs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268636 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index aca760810efde861091129ae2241a56653254dfa..fa5c491554ed85faddf1c2578b25357a72990a3f 100644 (file)
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -3948,6 +3948,27 @@ static Optional<bool> isImpliedCondMatchingOperands(CmpInst::Predicate APred,
   return None;
 }
 
+/// Return true if "icmp1 APred ALHS C1" implies "icmp2 BPred BLHS C2" is
+/// true.  Return false if "icmp1 APred ALHS C1" implies "icmp2 BPred BLHS
+/// C2" is false.  Otherwise, return None if we can't infer anything.
+static Optional<bool>
+isImpliedCondMatchingImmOperands(CmpInst::Predicate APred, Value *ALHS,
+                                 ConstantInt *C1, CmpInst::Predicate BPred,
+                                 Value *BLHS, ConstantInt *C2) {
+  assert(ALHS == BLHS && "LHS operands must match.");
+  ConstantRange DomCR =
+      ConstantRange::makeExactICmpRegion(APred, C1->getValue());
+  ConstantRange CR =
+      ConstantRange::makeAllowedICmpRegion(BPred, C2->getValue());
+  ConstantRange Intersection = DomCR.intersectWith(CR);
+  ConstantRange Difference = DomCR.difference(CR);
+  if (Intersection.isEmptySet())
+    return false;
+  if (Difference.isEmptySet())
+    return true;
+  return None;
+}
+
 Optional<bool> llvm::isImpliedCondition(Value *LHS, Value *RHS,
                                         const DataLayout &DL, bool InvertAPred,
                                         unsigned Depth, AssumptionCache *AC,
@@ -3985,6 +4006,14 @@ Optional<bool> llvm::isImpliedCondition(Value *LHS, Value *RHS,
   if (Implication)
     return Implication;
 
+  if (ALHS == BLHS && isa<ConstantInt>(ARHS) && isa<ConstantInt>(BRHS)) {
+    Implication =
+        isImpliedCondMatchingImmOperands(APred, ALHS, cast<ConstantInt>(ARHS),
+                                         BPred, BLHS, cast<ConstantInt>(BRHS));
+    if (Implication)
+      return Implication;
+  }
+
   if (APred == BPred)
     return isImpliedCondOperands(APred, ALHS, ARHS, BLHS, BRHS, DL, Depth, AC,
                                  CxtI, DT);

diff --git a/test/CodeGen/AArch64/addsub.ll b/test/CodeGen/AArch64/addsub.ll
index d6350a6db0eeb6a8562ea60f9044bb2d8899733d..c0235cd5d9ef37e739847f88d0eb3a9500044ba5 100644 (file)
--- a/test/CodeGen/AArch64/addsub.ll
+++ b/test/CodeGen/AArch64/addsub.ll
@@ -5,6 +5,7 @@
 ; loads and stores.
 
 @var_i32 = global i32 42
+@var2_i32 = global i32 43
 @var_i64 = global i64 0
 
 ; Add pure 12-bit immediates:
@@ -106,6 +107,7 @@ define void @sub_med() {
 define void @testing() {
 ; CHECK-LABEL: testing:
   %val = load i32, i32* @var_i32
+  %val2 = load i32, i32* @var2_i32
 
 ; CHECK: cmp {{w[0-9]+}}, #4095
 ; CHECK: b.ne [[RET:.?LBB[0-9]+_[0-9]+]]
@@ -117,7 +119,7 @@ test2:
 ; CHECK: b.lo [[RET]]
   %newval2 = add i32 %val, 1
   store i32 %newval2, i32* @var_i32
-  %cmp_pos_big = icmp ult i32 %val, 14610432
+  %cmp_pos_big = icmp ult i32 %val2, 14610432
   br i1 %cmp_pos_big, label %ret, label %test3
 
 test3:
@@ -133,7 +135,7 @@ test4:
 ; CHECK: b.gt [[RET]]
   %newval4 = add i32 %val, 3
   store i32 %newval4, i32* @var_i32
-  %cmp_pos_sgt = icmp sgt i32 %val, 321
+  %cmp_pos_sgt = icmp sgt i32 %val2, 321
   br i1 %cmp_pos_sgt, label %ret, label %test5
 
 test5:
@@ -141,7 +143,7 @@ test5:
 ; CHECK: b.gt [[RET]]
   %newval5 = add i32 %val, 4
   store i32 %newval5, i32* @var_i32
-  %cmp_neg_uge = icmp sgt i32 %val, -444
+  %cmp_neg_uge = icmp sgt i32 %val2, -444
   br i1 %cmp_neg_uge, label %ret, label %test6
 
 test6:

diff --git a/test/CodeGen/AArch64/combine-comparisons-by-cse.ll b/test/CodeGen/AArch64/combine-comparisons-by-cse.ll
index 59b4c953ee9f3640376ff9283a1c22209f32479d..1f8e0efa067581d3fdd61522179eafcf96f6f7a7 100644 (file)
--- a/test/CodeGen/AArch64/combine-comparisons-by-cse.ll
+++ b/test/CodeGen/AArch64/combine-comparisons-by-cse.ll
@@ -405,11 +405,11 @@ return:                                           ; preds = %land.lhs.true, %con
 
 define void @cmp_shifted(i32 %in, i32 %lhs, i32 %rhs) {
 ; CHECK-LABEL: cmp_shifted:
-; CHECK: cmp w0, #1
-; [...]
 ; CHECK: cmp w0, #2, lsl #12
+; [...]
+; CHECK: cmp w0, #1
 
-  %tst_low = icmp sgt i32 %in, 0
+  %tst_low = icmp sgt i32 %in, 8191
   br i1 %tst_low, label %true, label %false
 
 true:
@@ -417,7 +417,7 @@ true:
   ret void
 
 false:
-  %tst = icmp sgt i32 %in, 8191
+  %tst = icmp sgt i32 %in, 0
   br i1 %tst, label %truer, label %falser
 
 truer:

diff --git a/test/Transforms/InstCombine/select-implied.ll b/test/Transforms/InstCombine/select-implied.ll
index 0616bd97fd315e526d4a4c24a40aeb7a0be1da61..2100e3eae0089a3161f41ecbbc070b16d509b0ae 100644 (file)
--- a/test/Transforms/InstCombine/select-implied.ll
+++ b/test/Transforms/InstCombine/select-implied.ll
@@ -40,7 +40,7 @@ end:
 ; CHECK-LABEL: @test3
 ; CHECK-NOT: select
 ; CHECK: call void @foo(i32 30)
-define void @test3(i32 %a, i32 %b) {
+define void @test3(i32 %a) {
   %cmp1 = icmp ugt i32 %a, 10
   br i1 %cmp1, label %taken, label %end
 
@@ -101,5 +101,23 @@ ret:
   ret void
 }
 
+; A >u 10 implies A >u 9 is true.
+; CHECK-LABEL: @test5
+; CHECK-NOT: select
+; CHECK: call void @foo(i32 30)
+define void @test5(i32 %a) {
+  %cmp1 = icmp ugt i32 %a, 10
+  br i1 %cmp1, label %taken, label %end
+
+taken:
+  %cmp2 = icmp ugt i32 %a, 9
+  %c = select i1 %cmp2, i32 30, i32 0
+  call void @foo(i32 %c)
+  br label %end
+
+end:
+  ret void
+}
+
 declare void @foo(i32)
 declare i32 @bar(i32)

diff --git a/test/Transforms/SimplifyCFG/implied-cond-matching-imm.ll b/test/Transforms/SimplifyCFG/implied-cond-matching-imm.ll
new file mode 100644 (file)
index 0000000..60ef813
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/implied-cond-matching-imm.ll
@@ -0,0 +1,123 @@
+; RUN: opt %s -S -simplifycfg | FileCheck %s
+
+; cmp1 implies cmp2 is false
+; CHECK-LABEL: @test1
+; CHECK-NOT: call void @is(i1 true)
+; CHECK: call void @is(i1 false)
+define void @test1(i32 %a) {
+  %cmp1 = icmp eq i32 %a, 0
+  br i1 %cmp1, label %taken, label %untaken
+
+taken:
+  %cmp2 = icmp eq i32 %a, 1
+  br i1 %cmp2, label %istrue, label %isfalse
+
+istrue:
+  call void @is(i1 true)
+  ret void
+
+isfalse:
+  call void @is(i1 false)
+  ret void
+
+untaken:
+  ret void
+}
+
+; cmp1 implies cmp2 is false
+; CHECK-LABEL: @test2
+; CHECK-NOT: call void @is(i1 true)
+; CHECK: call void @is(i1 false)
+define void @test2(i32 %a) {
+  %cmp1 = icmp ugt i32 %a, 5
+  br i1 %cmp1, label %untaken, label %taken
+
+taken:
+  %cmp2 = icmp ugt i32 %a, 6
+  br i1 %cmp2, label %istrue, label %isfalse
+
+istrue:
+  call void @is(i1 true)
+  ret void
+
+isfalse:
+  call void @is(i1 false)
+  ret void
+
+untaken:
+  ret void
+}
+
+; cmp1 implies cmp2 is false
+; CHECK-LABEL: @test3
+; CHECK-NOT: call void @is(i1 true)
+; CHECK: call void @is(i1 false)
+define void @test3(i32 %a) {
+  %cmp1 = icmp ugt i32 %a, 1
+  br i1 %cmp1, label %taken, label %untaken
+
+taken:
+  %cmp2 = icmp eq i32 %a, 0
+  br i1 %cmp2, label %istrue, label %isfalse
+
+istrue:
+  call void @is(i1 true)
+  ret void
+
+isfalse:
+  call void @is(i1 false)
+  ret void
+
+untaken:
+  ret void
+}
+
+; cmp1 implies cmp2 is true
+; CHECK-LABEL: @test4
+; CHECK: call void @is(i1 true)
+; CHECK-NOT: call void @is(i1 false)
+define void @test4(i32 %a) {
+  %cmp1 = icmp sgt i32 %a, 1
+  br i1 %cmp1, label %taken, label %untaken
+
+taken:
+  %cmp2 = icmp ugt i32 %a, 0
+  br i1 %cmp2, label %istrue, label %isfalse
+
+istrue:
+  call void @is(i1 true)
+  ret void
+
+isfalse:
+  call void @is(i1 false)
+  ret void
+
+untaken:
+  ret void
+}
+
+; cmp1 implies cmp2 is true
+; CHECK-LABEL: @test5
+; CHECK: call void @is(i1 true)
+; CHECK-NOT: call void @is(i1 false)
+define void @test5(i32 %a) {
+  %cmp1 = icmp sgt i32 %a, 5
+  br i1 %cmp1, label %taken, label %untaken
+
+taken:
+  %cmp2 = icmp sgt i32 %a, -1
+  br i1 %cmp2, label %istrue, label %isfalse
+
+istrue:
+  call void @is(i1 true)
+  ret void
+
+isfalse:
+  call void @is(i1 false)
+  ret void
+
+untaken:
+  ret void
+}
+
+declare void @is(i1)