[llvm] [DAGCombiner] Fold patterm for srl-shl-zext (PR #138290)

[Craig Topper via llvm-commits]

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@@ -0,0 +1,40 @@
+; RUN: llc < %s -mtriple=nvptx64 | FileCheck %s
+
+define i64 @test1(i64 %x, i32 %y) {
+;
+; srl (or (x, shl(zext(y),c1)),c1) -> or(srl(x,c1), zext(y))
+; c1 <= leadingzeros(zext(y))
+;
+; CHECK-LABEL: test1
+; CHECK: ld.param.u64 %[[X:rd[0-9]+]], [test1_param_0];
+; CHECK: ld.param.u32 %[[Y:rd[0-9]+]], [test1_param_1];
+; CHECK: shr.u64      %[[SHR:rd[0-9]+]], %[[X]], 5;
+; CHECK: or.b64       %[[OR:rd[0-9]+]], %[[SHR]], %[[Y]];
+; CHECK: st.param.b64 [func_retval0], %[[OR]];
+;
+  %ext = zext i32 %y to i64
+  %shl = shl i64 %ext, 5
+  %or = or i64 %x, %shl
+  %srl = lshr i64 %or, 5
+  ret i64 %srl
+}
+
+define i64 @test2(i64 %x, i32 %y) {
+;
+; srl (or (x, shl(zext(y),c1)),c1) -> or(srl(x,c1), zext(y))
+; c1 > leadingzeros(zext(y)).
+;
+; CHECK-LABEL: test2
+; CHECK: ld.param.u64 %[[X:rd[0-9]+]], [test2_param_0];
+; CHECK: ld.param.u32 %[[Y:rd[0-9]+]], [test2_param_1];
+; CHECK: shl.b64      %[[SHL:rd[0-9]+]], %[[Y]], 33;
+; CHECK: or.b64       %[[OR:rd[0-9]+]], %[[X]], %[[SHL]];
+; CHECK: shr.u64      %[[SHR:rd[0-9]+]], %[[OR]], 33;
+; CHECK: st.param.b64 [func_retval0], %[[SHR]];
+;
+  %ext = zext i32 %y to i64
+  %shl = shl i64 %ext, 33
+  %or = or i64 %x, %shl
+  %srl = lshr i64 %or, 33
+  ret i64 %srl
+}
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topperc wrote:

Missing tests for vectors.

https://github.com/llvm/llvm-project/pull/138290