[llvm] [CGP][AArch64] Rebase the common base offset for better ISel (PR #74046)

[David Green via llvm-commits]

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@@ -209,3 +209,90 @@ define void @t17(i64 %a) {
   %3 = load volatile i64, ptr %2, align 8
   ret void
 }
+
+define i32 @LdOffset_i8(ptr %a)  {
+; CHECK-LABEL: LdOffset_i8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #56952 // =0xde78
+; CHECK-NEXT:    movk w8, #15, lsl #16
+; CHECK-NEXT:    ldrb w0, [x0, x8]
+; CHECK-NEXT:    ret
+  %arrayidx = getelementptr inbounds i8, ptr %a, i64 1039992
+  %val = load i8, ptr %arrayidx, align 1
+  %conv = zext i8 %val to i32
+  ret i32 %conv
+}
+
+define i32 @LdOffset_i16(ptr %a)  {
+; CHECK-LABEL: LdOffset_i16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #48368 // =0xbcf0
+; CHECK-NEXT:    movk w8, #31, lsl #16
+; CHECK-NEXT:    ldrsh w0, [x0, x8]
+; CHECK-NEXT:    ret
+  %arrayidx = getelementptr inbounds i16, ptr %a, i64 1039992
+  %val = load i16, ptr %arrayidx, align 2
+  %conv = sext i16 %val to i32
+  ret i32 %conv
+}
+
+define i32 @LdOffset_i32(ptr %a)  {
+; CHECK-LABEL: LdOffset_i32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #31200 // =0x79e0
+; CHECK-NEXT:    movk w8, #63, lsl #16
+; CHECK-NEXT:    ldr w0, [x0, x8]
+; CHECK-NEXT:    ret
+  %arrayidx = getelementptr inbounds i32, ptr %a, i64 1039992
+  %val = load i32, ptr %arrayidx, align 4
+  ret i32 %val
+}
+
+; https://gcc.godbolt.org/z/q6frE9ePe
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davemgreen wrote:

Remove the godbolt links

https://github.com/llvm/llvm-project/pull/74046