[llvm] Adjust bit cast instruction filter for DXIL Prepare pass (PR #142678)

[Joshua Batista via llvm-commits]

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@@ -0,0 +1,43 @@
+; RUN: opt -S --dxil-prepare %s | FileCheck %s
+
+; Test that global arrays do not get a bitcast instruction
+; after the dxil-prepare pass.
+
+target triple = "dxilv1.2-unknown-shadermodel6.2-compute"
+
+ at inputTile.1dim = local_unnamed_addr addrspace(3) global [3 x float] zeroinitializer, align 2
+
+; CHECK-LABEL: testload
+define float @testload() local_unnamed_addr {
+  ; NOTE: this would be "bitcast ptr addrspace(3)..." before the change that introduced this test,
+  ; after the dxil-prepare pass is run
+  ; CHECK-NEXT: load float, ptr addrspace(3) @inputTile.1dim, align 2
+  %v = load float, ptr addrspace(3) @inputTile.1dim, align 2  
+  
+  ret float %v
+}
+
+; CHECK-LABEL: teststore
+define void @teststore() local_unnamed_addr {  
+  ; CHECK-next: store float 2.000000e+00, ptr addrspace(3) @inputTile.1dim, align 2
+  store float 2.000000e+00, ptr addrspace(3) @inputTile.1dim, align 2  
+  
+  ret void
+}
+
+; CHECK-LABEL: testGEPConst
+define float @testGEPConst() local_unnamed_addr {  
+  ; CHECK-NEXT: load float, ptr addrspace(3) getelementptr (float, ptr addrspace(3) @inputTile.1dim, i32 1), align 4
+  %v = load float, ptr addrspace(3) getelementptr (float, ptr addrspace(3) @inputTile.1dim, i32 1), align 4
+  
+  ret float %v
+}
+
+; CHECK-LABEL: testGEPNonConst
+define float @testGEPNonConst(i32 %i) local_unnamed_addr {  
+  ; CHECK-NEXT: getelementptr float, ptr addrspace(3) @inputTile.1dim, i32 %i
+  %gep = getelementptr float, ptr addrspace(3) @inputTile.1dim, i32 %i
+  %v = load float, ptr addrspace(3) %gep
+  
+  ret float %v
+}
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bob80905 wrote:

Working on it, I had thought my change didn't include that alloca case and forgot that that went in too.

https://github.com/llvm/llvm-project/pull/142678