[Autobackout][FunctionalRegression]Revert of change: 5089830: Removei…

…ng dead code Couldn't produce a test to hit removed code. The maximum (power of 2) value you can store in any iXX variable is 2^XX-1. The 2^XX can't fit into iXX
intel · Sep 20, 2024 · e22d8fd · e22d8fd
1 parent 2f01e0a
commit e22d8fd
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Showing 2 changed files with 5 additions and 13 deletions.
diff --git a/IGC/Compiler/Optimizer/IntDivConstantReduction.cpp b/IGC/Compiler/Optimizer/IntDivConstantReduction.cpp
@@ -170,8 +170,11 @@ struct IntDivConstantReduction : public FunctionPass
  int shiftAmt = divisor.logBase2();
  Value *result;
  if (isMod) {
- // X % 2^K = (X & ((1<<K)-1))
- result = B.CreateAnd(dividend, ((1ull << shiftAmt)-1));
+ if (shiftAmt == bitSize) { // X % MAX_VAL = X
+ result = dividend;
+ } else { // X % 2^K = (X & ((1<<K)-1))
+ result = B.CreateAnd(dividend, ((1ull << shiftAmt)-1));
+ }
  } else {
  result = B.CreateLShr(dividend, shiftAmt);
  }

diff --git a/IGC/Compiler/tests/IntDivConstantReduction/basic.ll b/IGC/Compiler/tests/IntDivConstantReduction/basic.ll
@@ -135,17 +135,6 @@ define spir_kernel void @test_sdiv_max(i32 %src1) {
  ret void
 }
 
-define spir_kernel void @test_rem_pow_of_2(i32 %src1) {
-; CHECK-LABEL: @test_rem_pow_of_2(
-; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[SRC1:%.*]], 2147483647
-; CHECK-NEXT: call void @use.i32(i32 [[TMP1]])
-; CHECK-NEXT: ret void
-;
- %1 = urem i32 %src1, 2147483648 ; <- 2^31
- call void @use.i32(i32 %1)
- ret void
-}
-
 define spir_kernel void @test_udiv_max(i32 %src1) {
 ; CHECK-LABEL: @test_udiv_max(
 ; CHECK: [[Q_APPX:%.*]] = call i32 @llvm.genx.GenISA.umulH.i32(i32 %src1, i32 -2147483647)