[CVP] Deduce no-wrap on mul

LebedevRI · LebedevRI · commit 3ddad0b0b188 · 2019-10-21T08:21:44.000Z
Summary: `ConstantRange::makeGuaranteedNoWrapRegion()` knows how to deal with `mul` since rL335646, there is exhaustive test coverage. This is already used by CVP's `processOverflowIntrinsic()`, and by SCEV's `StrengthenNoWrapFlags()` That being said, currently, this doesn't help much in the end: | statistic | old | new | delta | percentage | | correlated-value-propagation.NumMulNSW | 4 | 275 | 271 | 6775.00% | | correlated-value-propagation.NumMulNUW | 4 | 1323 | 1319 | 32975.00% | | correlated-value-propagation.NumMulNW | 8 | 1598 | 1590 | 19875.00% | | correlated-value-propagation.NumNSW | 5715 | 5986 | 271 | 4.74% | | correlated-value-propagation.NumNUW | 9193 | 10512 | 1319 | 14.35% | | correlated-value-propagation.NumNW | 14908 | 16498 | 1590 | 10.67% | | instcount.NumAddInst | 275871 | 275869 | -2 | 0.00% | | instcount.NumBrInst | 708234 | 708232 | -2 | 0.00% | | instcount.NumMulInst | 43812 | 43810 | -2 | 0.00% | | instcount.NumPHIInst | 316786 | 316784 | -2 | 0.00% | | instcount.NumTruncInst | 62165 | 62167 | 2 | 0.00% | | instcount.NumUDivInst | 2528 | 2526 | -2 | -0.08% | | instcount.TotalBlocks | 842995 | 842993 | -2 | 0.00% | | instcount.TotalInsts | 7376486 | 7376478 | -8 | 0.00% | (^ test-suite plain, tests still pass) Reviewers: nikic, reames, luqmana, sanjoy, timshen Reviewed By: reames Subscribers: hiraditya, javed.absar, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D69203 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375396 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -860,6 +860,7 @@ static bool runImpl(Function &F, LazyValueInfo *LVI, DominatorTree *DT,
         break;
       case Instruction::Add:
       case Instruction::Sub:
+      case Instruction::Mul:
         BBChanged |= processBinOp(cast<BinaryOperator>(II), LVI);
         break;
       case Instruction::And:
diff --git a/test/Transforms/CorrelatedValuePropagation/mul.ll b/test/Transforms/CorrelatedValuePropagation/mul.ll
@@ -7,7 +7,7 @@ define i8 @test0(i8 %a) {
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i8 [[A:%.*]], 3
 ; CHECK-NEXT:    br i1 [[CMP]], label [[BB:%.*]], label [[EXIT:%.*]]
 ; CHECK:       bb:
-; CHECK-NEXT:    [[MUL:%.*]] = mul i8 [[A]], 50
+; CHECK-NEXT:    [[MUL:%.*]] = mul nuw nsw i8 [[A]], 50
 ; CHECK-NEXT:    ret i8 [[MUL]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret i8 0
@@ -30,7 +30,7 @@ define i8 @test1(i8 %a) {
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i8 [[A:%.*]], 4
 ; CHECK-NEXT:    br i1 [[CMP]], label [[BB:%.*]], label [[EXIT:%.*]]
 ; CHECK:       bb:
-; CHECK-NEXT:    [[MUL:%.*]] = mul i8 [[A]], 50
+; CHECK-NEXT:    [[MUL:%.*]] = mul nuw i8 [[A]], 50
 ; CHECK-NEXT:    ret i8 [[MUL]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret i8 0
@@ -53,7 +53,7 @@ define i8 @test2(i8 %a) {
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i8 [[A:%.*]], 6
 ; CHECK-NEXT:    br i1 [[CMP]], label [[BB:%.*]], label [[EXIT:%.*]]
 ; CHECK:       bb:
-; CHECK-NEXT:    [[MUL:%.*]] = mul i8 [[A]], 50
+; CHECK-NEXT:    [[MUL:%.*]] = mul nuw i8 [[A]], 50
 ; CHECK-NEXT:    ret i8 [[MUL]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret i8 0
@@ -101,7 +101,7 @@ define i8 @test4(i8 %a) {
 ; CHECK-NEXT:    [[COND:%.*]] = and i1 [[CMP1]], [[CMP2]]
 ; CHECK-NEXT:    br i1 [[COND]], label [[BB:%.*]], label [[EXIT:%.*]]
 ; CHECK:       bb:
-; CHECK-NEXT:    [[MUL:%.*]] = mul i8 [[A]], 50
+; CHECK-NEXT:    [[MUL:%.*]] = mul nsw i8 [[A]], 50
 ; CHECK-NEXT:    ret i8 [[MUL]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret i8 0
