Re-commit "[RISCV] Properly support RISCVISD::LLA in getTargetConstantFromLoad. (#145112)"

With proper co-author.

Original message:

We need to pass the operand of LLA to GetSupportedConstantPool.

This replaces #142292 with test from there added as a pre-commit
for both medlow and pic.

Co-authored-by: Carl Nettelblad carl.nettelblad@rapidity-space.com

Author: topperc

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -21062,7 +21062,7 @@ RISCVTargetLowering::getTargetConstantFromLoad(LoadSDNode *Ld) const {
 
   // Simple case, LLA.
   if (Ptr.getOpcode() == RISCVISD::LLA) {
-    auto *CNode = GetSupportedConstantPool(Ptr);
+    auto *CNode = GetSupportedConstantPool(Ptr.getOperand(0));
     if (!CNode || CNode->getTargetFlags() != 0)
       return nullptr;
 

llvm/test/CodeGen/RISCV/constpool-known-bits.ll

@@ -0,0 +1,69 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s -O0 -mtriple=riscv64 -mattr=+m | FileCheck %s --check-prefix=NOPIC
+; RUN: llc < %s -O0 -mtriple=riscv64 -mattr=+m -relocation-model=pic | FileCheck %s --check-prefix=PIC
+
+define i64 @test(i32 noundef signext %c, i32 noundef signext %d) {
+; NOPIC-LABEL: test:
+; NOPIC:       # %bb.0: # %entry
+; NOPIC-NEXT:    # kill: def $x11 killed $x10
+; NOPIC-NEXT:    slli a0, a0, 32
+; NOPIC-NEXT:    srli a1, a0, 32
+; NOPIC-NEXT:    lui a0, %hi(.LCPI0_0)
+; NOPIC-NEXT:    ld a0, %lo(.LCPI0_0)(a0)
+; NOPIC-NEXT:    mul a0, a1, a0
+; NOPIC-NEXT:    addi a0, a0, 127
+; NOPIC-NEXT:    mul a0, a1, a0
+; NOPIC-NEXT:    lui a2, %hi(.LCPI0_1)
+; NOPIC-NEXT:    ld a2, %lo(.LCPI0_1)(a2)
+; NOPIC-NEXT:    mul a0, a0, a2
+; NOPIC-NEXT:    add a0, a0, a1
+; NOPIC-NEXT:    lui a1, 1015920
+; NOPIC-NEXT:    addi a1, a1, 1541
+; NOPIC-NEXT:    slli a1, a1, 16
+; NOPIC-NEXT:    addi a1, a1, 1027
+; NOPIC-NEXT:    slli a1, a1, 20
+; NOPIC-NEXT:    add a0, a0, a1
+; NOPIC-NEXT:    ret
+;
+; PIC-LABEL: test:
+; PIC:       # %bb.0: # %entry
+; PIC-NEXT:    # kill: def $x11 killed $x10
+; PIC-NEXT:    slli a0, a0, 32
+; PIC-NEXT:    srli a1, a0, 32
+; PIC-NEXT:  .Lpcrel_hi0:
+; PIC-NEXT:    auipc a0, %pcrel_hi(.LCPI0_0)
+; PIC-NEXT:    addi a0, a0, %pcrel_lo(.Lpcrel_hi0)
+; PIC-NEXT:    ld a0, 0(a0)
+; PIC-NEXT:    mul a0, a1, a0
+; PIC-NEXT:    addi a0, a0, 127
+; PIC-NEXT:    mul a0, a1, a0
+; PIC-NEXT:  .Lpcrel_hi1:
+; PIC-NEXT:    auipc a2, %pcrel_hi(.LCPI0_1)
+; PIC-NEXT:    addi a2, a2, %pcrel_lo(.Lpcrel_hi1)
+; PIC-NEXT:    ld a2, 0(a2)
+; PIC-NEXT:    mul a0, a0, a2
+; PIC-NEXT:    add a0, a0, a1
+; PIC-NEXT:    lui a1, 1015920
+; PIC-NEXT:    addi a1, a1, 1541
+; PIC-NEXT:    slli a1, a1, 16
+; PIC-NEXT:    addi a1, a1, 1027
+; PIC-NEXT:    slli a1, a1, 20
+; PIC-NEXT:    add a0, a0, a1
+; PIC-NEXT:    ret
+entry:
+  %or1 = or i64 -9191740941672644608, 4096
+  %or2 = or i64 -9191740941672644608, 8192
+  %or3 = or i64 -9191740941672644608, 16384
+  %conv = zext i32 %c to i64
+  %donv = zext i32 %d to i64
+  %3 = mul i64 %or1, %conv
+  %4 = mul i64 %or2, %donv
+  %5 = mul i64 %or3, %conv
+  %6 = add i64 %3, %4
+  %7 = add i64 %6, %5
+  %8 = or i64 %5, 127
+  %9 = mul i64 %3, %8
+  %add = add i64 -9191740941672644608, %9
+  %add2 = add i64 %add, %conv
+  ret i64 %add2
+}