From: Roman Lebedev <lebedev.ri@gmail.com>
Date: Sat, 31 Dec 2022 01:58:22 +0000 (+0300)
Subject: [CVP] When expanding `urem`, always freeze the nominator
X-Git-Tag: upstream/17.0.6~22420
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=08c2f4eb7ab3e75eb9d2048f73ea9874c663fb5a;p=platform%2Fupstream%2Fllvm.git

[CVP] When expanding `urem`, always freeze the nominator

As per the post-commit feedback - that was not the correct precondition
to avoid it here. I think we should generally start changing mentality
about `freeze`, the fact that we have been conditioned to be afraid of it
(or of anything in LLVM in general) is the key problem here.
---

diff --git a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
index 1093f4e..fdebd6f 100644
--- a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
+++ b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -801,21 +801,16 @@ static bool expandURem(BinaryOperator *Instr, LazyValueInfo *LVI) {
   //   R  = X* % Y                 iff X* u< 2*Y (w/ unsigned saturation)
   // but that does not seem profitable here.
 
-  bool XIsBound =
-      XCR.icmp(ICmpInst::ICMP_ULT, YCR.umul_sat(APInt(YCR.getBitWidth(), 2)));
   // Even if we don't know X's range, the divisor may be so large, X can't ever
   // be 2x larger than that. I.e. if divisor is always negative.
-  if (!XIsBound && !YCR.isAllNegative())
+  if (!XCR.icmp(ICmpInst::ICMP_ULT,
+                YCR.umul_sat(APInt(YCR.getBitWidth(), 2))) &&
+      !YCR.isAllNegative())
     return false;
-
   IRBuilder<> B{Instr};
-  if (!XIsBound) {
-    // NOTE: this transformation increases use count on X, but that is fine
-    // unless the transformation is valid because the divisor is negative,
-    // and is non-variable, and thus we didn't have any extra uses.
-    if (auto *Ycst = dyn_cast<ConstantInt>(Y); Ycst && Ycst->isNegative())
-      X = B.CreateFreeze(X, X->getName() + ".frozen");
-  }
+  // NOTE: this transformation introduces two uses of X,
+  //       but it may be undef so we must freeze it first.
+  X = B.CreateFreeze(X, X->getName() + ".frozen");
   auto *AdjX = B.CreateNUWSub(X, Y, Instr->getName() + ".urem");
   auto *Cmp = B.CreateICmp(ICmpInst::ICMP_ULT, X, Y, Instr->getName() + ".cmp");
   auto *ExpandedURem = B.CreateSelect(Cmp, X, AdjX);
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/urem-expansion.ll b/llvm/test/Transforms/CorrelatedValuePropagation/urem-expansion.ll
index 36d9771..620cd5e 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/urem-expansion.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/urem-expansion.ll
@@ -20,9 +20,10 @@ define i8 @constant.divisor.v4(i8 %x) {
 ; CHECK-LABEL: @constant.divisor.v4(
 ; CHECK-NEXT:    [[CMP_X_UPPER:%.*]] = icmp ult i8 [[X:%.*]], 4
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP_X_UPPER]])
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], 3
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], 3
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], 3
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], 3
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %cmp.x.upper = icmp ult i8 %x, 4
@@ -33,9 +34,10 @@ define i8 @constant.divisor.v4(i8 %x) {
 define i8 @constant.divisor.x.range.v4(ptr %x.ptr) {
 ; CHECK-LABEL: @constant.divisor.x.range.v4(
 ; CHECK-NEXT:    [[X:%.*]] = load i8, ptr [[X_PTR:%.*]], align 1, !range [[RNG0:![0-9]+]]
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], 3
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], 3
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], 3
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], 3
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %x = load i8, ptr %x.ptr, !range !{ i8 0, i8 4 }
@@ -45,9 +47,10 @@ define i8 @constant.divisor.x.range.v4(ptr %x.ptr) {
 define i8 @constant.divisor.x.mask.v4(i8 %x) {
 ; CHECK-LABEL: @constant.divisor.x.mask.v4(
 ; CHECK-NEXT:    [[X_MASKED:%.*]] = and i8 [[X:%.*]], 3
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_MASKED]], 3
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_MASKED]], 3
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_MASKED]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_MASKED_FROZEN:%.*]] = freeze i8 [[X_MASKED]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_MASKED_FROZEN]], 3
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_MASKED_FROZEN]], 3
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_MASKED_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %x.masked = and i8 %x, 3
@@ -58,9 +61,10 @@ define i8 @constant.divisor.v5(i8 %x) {
 ; CHECK-LABEL: @constant.divisor.v5(
 ; CHECK-NEXT:    [[CMP_X_UPPER:%.*]] = icmp ult i8 [[X:%.*]], 5
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP_X_UPPER]])
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], 3
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], 3
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], 3
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], 3
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %cmp.x.upper = icmp ult i8 %x, 5
@@ -72,9 +76,10 @@ define i8 @constant.divisor.v6(i8 %x) {
 ; CHECK-LABEL: @constant.divisor.v6(
 ; CHECK-NEXT:    [[CMP_X_UPPER:%.*]] = icmp ult i8 [[X:%.*]], 6
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP_X_UPPER]])
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], 3
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], 3
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], 3
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], 3
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %cmp.x.upper = icmp ult i8 %x, 6
@@ -124,9 +129,10 @@ define i8 @variable.v4(i8 %x, i8 %y) {
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP_Y_LOWER]])
 ; CHECK-NEXT:    [[CMP_Y_UPPER:%.*]] = icmp ule i8 [[Y]], 4
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP_Y_UPPER]])
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], [[Y]]
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], [[Y]]
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %cmp.x = icmp ult i8 %x, 4
@@ -142,9 +148,10 @@ define i8 @variable.v4.range(ptr %x.ptr, ptr %y.ptr) {
 ; CHECK-LABEL: @variable.v4.range(
 ; CHECK-NEXT:    [[X:%.*]] = load i8, ptr [[X_PTR:%.*]], align 1, !range [[RNG0]]
 ; CHECK-NEXT:    [[Y:%.*]] = load i8, ptr [[Y_PTR:%.*]], align 1, !range [[RNG1:![0-9]+]]
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], [[Y]]
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], [[Y]]
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %x = load i8, ptr %x.ptr, !range !{ i8 0, i8 4 }
@@ -160,9 +167,10 @@ define i8 @variable.v5(i8 %x, i8 %y) {
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP_Y_LOWER]])
 ; CHECK-NEXT:    [[CMP_Y_UPPER:%.*]] = icmp ule i8 [[Y]], 4
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP_Y_UPPER]])
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], [[Y]]
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], [[Y]]
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %cmp.x = icmp ult i8 %x, 5
@@ -182,9 +190,10 @@ define i8 @variable.v6(i8 %x, i8 %y) {
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP_Y_LOWER]])
 ; CHECK-NEXT:    [[CMP_Y_UPPER:%.*]] = icmp ule i8 [[Y]], 4
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP_Y_UPPER]])
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], [[Y]]
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], [[Y]]
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], [[Y]]
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %cmp.x = icmp ult i8 %x, 6
@@ -234,9 +243,10 @@ define i8 @large.divisor.v1(i8 %x) {
 ; CHECK-LABEL: @large.divisor.v1(
 ; CHECK-NEXT:    [[CMP_X_UPPER:%.*]] = icmp ult i8 [[X:%.*]], -128
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP_X_UPPER]])
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], 127
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], 127
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], 127
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], 127
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %cmp.x.upper = icmp ult i8 %x, 128
@@ -247,9 +257,10 @@ define i8 @large.divisor.v1(i8 %x) {
 define i8 @large.divisor.v1.range(ptr %x.ptr) {
 ; CHECK-LABEL: @large.divisor.v1.range(
 ; CHECK-NEXT:    [[X:%.*]] = load i8, ptr [[X_PTR:%.*]], align 1, !range [[RNG2:![0-9]+]]
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], 127
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], 127
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], 127
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], 127
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %x = load i8, ptr %x.ptr, !range !{ i8 0, i8 128 }
@@ -280,9 +291,10 @@ define i8 @large.divisor.with.overflow.v1(i8 %x) {
 ; CHECK-LABEL: @large.divisor.with.overflow.v1(
 ; CHECK-NEXT:    [[CMP_X_UPPER:%.*]] = icmp ult i8 [[X:%.*]], -127
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP_X_UPPER]])
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], -128
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], -128
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], -128
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], -128
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %cmp.x.upper = icmp ult i8 %x, 129
@@ -293,9 +305,10 @@ define i8 @large.divisor.with.overflow.v1(i8 %x) {
 define i8 @large.divisor.with.overflow.v1.range(ptr %x.ptr) {
 ; CHECK-LABEL: @large.divisor.with.overflow.v1.range(
 ; CHECK-NEXT:    [[X:%.*]] = load i8, ptr [[X_PTR:%.*]], align 1, !range [[RNG3:![0-9]+]]
-; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X]], -128
-; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X]], -128
-; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X]], i8 [[REM_UREM]]
+; CHECK-NEXT:    [[X_FROZEN:%.*]] = freeze i8 [[X]]
+; CHECK-NEXT:    [[REM_UREM:%.*]] = sub nuw i8 [[X_FROZEN]], -128
+; CHECK-NEXT:    [[REM_CMP:%.*]] = icmp ult i8 [[X_FROZEN]], -128
+; CHECK-NEXT:    [[REM:%.*]] = select i1 [[REM_CMP]], i8 [[X_FROZEN]], i8 [[REM_UREM]]
 ; CHECK-NEXT:    ret i8 [[REM]]
 ;
   %x = load i8, ptr %x.ptr, !range !{ i8 0, i8 129 }
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/urem.ll b/llvm/test/Transforms/CorrelatedValuePropagation/urem.ll
index 19dfc68..b9c112c 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/urem.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/urem.ll
@@ -117,9 +117,10 @@ exit:
 define void @test5(i32 %n) {
 ; CHECK-LABEL: @test5(
 ; CHECK-NEXT:    [[TRUNC:%.*]] = and i32 [[N:%.*]], 63
-; CHECK-NEXT:    [[DIV_UREM:%.*]] = sub nuw i32 [[TRUNC]], 42
-; CHECK-NEXT:    [[DIV_CMP:%.*]] = icmp ult i32 [[TRUNC]], 42
-; CHECK-NEXT:    [[DIV:%.*]] = select i1 [[DIV_CMP]], i32 [[TRUNC]], i32 [[DIV_UREM]]
+; CHECK-NEXT:    [[TRUNC_FROZEN:%.*]] = freeze i32 [[TRUNC]]
+; CHECK-NEXT:    [[DIV_UREM:%.*]] = sub nuw i32 [[TRUNC_FROZEN]], 42
+; CHECK-NEXT:    [[DIV_CMP:%.*]] = icmp ult i32 [[TRUNC_FROZEN]], 42
+; CHECK-NEXT:    [[DIV:%.*]] = select i1 [[DIV_CMP]], i32 [[TRUNC_FROZEN]], i32 [[DIV_UREM]]
 ; CHECK-NEXT:    ret void
 ;
   %trunc = and i32 %n, 63
diff --git a/llvm/test/Transforms/PhaseOrdering/cmp-logic.ll b/llvm/test/Transforms/PhaseOrdering/cmp-logic.ll
index 008e88e..04eae7d 100644
--- a/llvm/test/Transforms/PhaseOrdering/cmp-logic.ll
+++ b/llvm/test/Transforms/PhaseOrdering/cmp-logic.ll
@@ -123,7 +123,8 @@ define i32 @PR56119(i32 %e.coerce) {
 ;
 ; OZ-LABEL: @PR56119(
 ; OZ-NEXT:  entry:
-; OZ-NEXT:    [[CONV2:%.*]] = and i32 [[E_COERCE:%.*]], 255
+; OZ-NEXT:    [[E_COERCE_FR:%.*]] = freeze i32 [[E_COERCE:%.*]]
+; OZ-NEXT:    [[CONV2:%.*]] = and i32 [[E_COERCE_FR]], 255
 ; OZ-NEXT:    [[CMP1:%.*]] = icmp eq i32 [[CONV2]], 7
 ; OZ-NEXT:    br i1 [[CMP1]], label [[IF_THEN:%.*]], label [[IF_END:%.*]]
 ; OZ:       if.then: