else { // Scalar
switch (Opcode) {
case Instruction::ICmp: {
+ // A loaded value compared with 0 with multiple users becomes Load and
+ // Test. The load is then not foldable, so return 0 cost for the ICmp.
+ unsigned ScalarBits = ValTy->getScalarSizeInBits();
+ if (I != nullptr && ScalarBits >= 32)
+ if (LoadInst *Ld = dyn_cast<LoadInst>(I->getOperand(0)))
+ if (const ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1)))
+ if (!Ld->hasOneUse() && Ld->getParent() == I->getParent() &&
+ C->getZExtValue() == 0)
+ return 0;
+
unsigned Cost = 1;
if (ValTy->isIntegerTy() && ValTy->getScalarSizeInBits() <= 16)
Cost += (I != nullptr ? getOperandsExtensionCost(I) : 2);
--- /dev/null
+; RUN: opt < %s -cost-model -analyze -mtriple=systemz-unknown -mcpu=z13 | FileCheck %s
+;
+; Test that load and test results in 0 cost for the compare.
+
+define i64 @fun0(i64* %Src, i64 %Arg) {
+ %Ld1 = load i64, i64* %Src
+ %Cmp = icmp eq i64 %Ld1, 0
+ %S = select i1 %Cmp, i64 %Arg, i64 %Ld1
+ ret i64 %S
+; CHECK: Printing analysis 'Cost Model Analysis' for function 'fun0':
+; CHECK: Cost Model: Found an estimated cost of 1 for instruction: %Ld1 = load i64, i64* %Src
+; CHECK: Cost Model: Found an estimated cost of 0 for instruction: %Cmp = icmp eq i64 %Ld1, 0
+; CHECK: Cost Model: Found an estimated cost of 1 for instruction: %S = select
+}
+
+define i32 @fun1(i32* %Src, i32 %Arg) {
+ %Ld1 = load i32, i32* %Src
+ %Cmp = icmp eq i32 %Ld1, 0
+ %S = select i1 %Cmp, i32 %Arg, i32 %Ld1
+ ret i32 %S
+; CHECK: Printing analysis 'Cost Model Analysis' for function 'fun1':
+; CHECK: Cost Model: Found an estimated cost of 1 for instruction: %Ld1 = load i32, i32* %Src
+; CHECK: Cost Model: Found an estimated cost of 0 for instruction: %Cmp = icmp eq i32 %Ld1, 0
+; CHECK: Cost Model: Found an estimated cost of 1 for instruction: %S = select
+}